1. elfloader for shared object
example: TencentOS-tiny\examples\elfloader_shared_object
keil: TencentOS-tiny\board\TencentOS_tiny_EVB_MX_Plus\KEIL\elfloader_shared_object

2. elfloader for relocatable object:
example: TencentOS-tiny\examples\elfloader_relocatable_object
keil: TencentOS-tiny\board\TencentOS_tiny_EVB_MX_Plus\KEIL\elfloader_relocatable_object

3. TODO:
- add icache/dcache flush when module is loaded
- support more relocation type in elfloader_arch_relocate

add lora reconnect code for pm2.5 project

1. see board\TencentOS_tiny_EVB_MX_Plus\KEIL\fatfs_through_vfs

1. effective "Differential Upgrade" patch algorithm with high compression rate
2. effective recovery algorithm support recovery firmware in blocks which has low memory consumption and wear-leveling strategies, especially suitable for embeded devices with low RAM.
3. add sample ota bootloader project, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_bootloader_recovery
4. add sample application project for download firmware through http, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_http
5. add sample application project for download firmware through qcloud explorer console, see:
board\TencentOS_tiny_EVB_MX_Plus\KEIL\ota\ota_application_download_through_qcloud_iot_explorer
6. an OTA markdown document is pending

add pm2.5 demo for evbmx+

fix cigcc  project

1. iot-hub sdk update to 3.2.0
2. iot-explorer update to 3.1.1

1. some calloc fix
2. fix some document error
3. refactor kv API, to be compatible with ota API

see：
doc/20.In_Application_Programming_based_EVB_MX_Plus.md

add mqtt client example for evb_mx+

add modbus demo for MX+

1. posix pthread.h: pthread, pthread_barrier, pthread_cond, pthread_mutex, , pthread_rwlock, pthread_spin, etc
2. posix semaphore.h: sem_*
3. posix mqueue.h: mq_*
4. posix time.h: timer_*
5. to support posix, add tos_barrier, tos_bitmap, tos_rwlock, tos_stopwatch, change name of k_task_t from a char * pointer to a char array.
6. sample, see examples\posix
7. project, see board\TencentOS_tiny_EVB_MX_Plus\KEIL\posix

fix MX and MXplus lora demo

simple, clear, easy to DIY

1. a true wear-leveling kv fs for norflash, especially optimize for some onchip norflash with "write once on one single write unit" like stm32l4, a true "no earse before write" flash algorithm.
2. an "as less as possible" gc strategy, do best to save norflash's life.
3. full "power down protection" support
4. see "examples" of kv, project in "TencentOS_tiny_EVB_MX_Plus", with onchip flash and qspiflash sample.

need meshctl installed on raspberrypi. nimble offical samples have a lot of pit ...

1. add TOS_CFG_LIBC_PRINTF_EN
1: enable printf to implement tos_kprintf
when you call tos_kprintf(actually currently it's a MACRO rather than a function) , the libc will be invloved into the image, most of the time it means a larger image size.

0: disable printf, means tos_kprintf is defined as an empty MACRO
most of the time, means you will not get a log output from the uart(currently we donnot have a console yet) but a smaller image size.

2. fix a bug of tos_mail_q and tos_priority_mail_q
if we are post-ing a mail and there is[are] task[s] just pend-ing for the mail queue, the mail delivered to the pend-er will be a pointer, and probably it's a pointer to the local variable on the stack. Actually we should do a memcpy rather than a pointer assignment. for more details, see the patch.

add nb-iot demo for huawei ocean_connect

1. qcloud has a great revolution, the protocol has been changed to implement data template, so the old TencentCloud_SDK developed by us will not work fine now(mqtt still works, but data template will not works fine for recently created product/devices).

2. I merge the official qlcoud sdk(include both the iot-hub and iot-explorer sdk) into the componet/conectivity to support new protocol of data template

3. iot-hub sdk, supply the fundamental iot protocol(like mqtt coap, etc.)
iot-explorer sdk, supply the high level service like data template based on mqtt

4. To know how it works, see qcloud_iot_explorer_sdk_data_template、qcloud_iot_hub_sdk_mqtt example(keil project in board\TencentOS_tiny_EVB_MX_Plus\KEIL\qcloud_iot_explorer_sdk_data_template and  board\TencentOS_tiny_EVB_MX_Plus\KEIL\qcloud_iot_hub_sdk_mqtt)

sample: examples\aliyun_iotkit_csdk_mqtt
project: board\TencentOS_tiny_EVB_MX_Plus\KEIL\aliyun_iotkit_csdk_mqtt

1. tos_ring_q_create_dyn
2. tos_chr_fifo_create_dyn
3. tos_msg_q_create_dyn
4. tos_mail_q_create_dyn
5. tos_bin_heap_create_dyn
6. tos_prio_q_create_dyn
7. tos_prio_msg_q_create_dyn
8. tos_prio_mail_q_create_dyn

add ring queue/message queue/mail queue, binary heap/priority queue/priority message queue/priority mail queue

1. remove the old msg queue and queue:
i. msg queue is not a common and reusable/flexible component(need user to config the msg pool size and this componet can only be used by tos_queue)
ii. tos_queue can only deliver the pointer message(cannot do a memory buffer deliver)

2. add ring queue(tos_ring_q) componet
rinq queue can be reused by tos_chr_fifi/tos_msg_q/tos_mail_q as the foundational data container

3. add message queue(tos_msg_q)
a little like the old queue mechanism, supply the capability to deliver a pointer message

4. add mail queue(tos_mail_q)
supply the capability to deliver a memory buffer

5. add binary heap(tos_bin_heap)
the basement componet to implement priority queue

6. add priority queue(tos_prio_q)
can be reused by the priority message/mail queue  as the foundational data container.

7. add priority message queue(tos_prio_msg_q)
a message(pointer) deliver mechanism, supply the capability of delivering the message with priority(message with higher priority comes faster to the pender than with lower)

8. add priority mail queue(tos_prio_mail_q)
a mail(memory buffer) deliver mechanism, supply the capability of delivering the mail with priority(mail with higher priority comes faster to the pender than with lower)

tos_task_create_dyn: create task with dynamic allocated task handler and stack
tos_task_walkthru: API to walk through the statistic list of all the existing task
tos_task_curr_task_get: get current running task handler