* modify HaaSPython's brief introduction, fix #1772
Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

* add HaaS Python v2.2.0 release notest, fix #1726
Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

* add README for HaaS EDU K1 examples, fix #1798
Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

* modify HaaSPython's brief introduction, fix #1772
Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

* add HaaS Python v2.2.0 release notest, fix #1726
Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

[Detail]
Fix documentation on UART API: on()
Improve examples in UART doc.

[Verified Cases]
Build Pass: None
Test Pass: None

[Detail]
Workaround for ethernet spi hardware to prevent dead loops.

[Verified Cases]
Build Pass: <helloworld_demo@haas100>
Test Pass: <helloworld_demo@haas100>

[Detail]
The CH395 ethernet chip on board is unstable for some reason.
Workaround for stable ethernet connection.

[Verified Cases]
Build Pass: <helloworld_demo@haas100>
Test Pass: <helloworld_demo@haas100>

Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

Use localtime/localtime_r and env apis in newlib libc, and remove
duplicate implementation in posix and newlib_stub_uspace.
Signed-off-by: NJinliang Li <ljl150821@alibaba-inc.com>

Signed-off-by: Nethan.lcz <ethan.lcz@alibaba-inc.com>

[Detail]
only for haas200 and haaseduk1.

[Verified Cases]
Build Pass: <none>
Test Pass: <none>

Change-Id: Ia8906bd90d52dc67b995a1ad8631d4ee606d83ce

Issue id: #1763 add security_monitoring_system demo
Solution: when megnetic sensor is triggered,buzzer will make sound and camera will caputure image and upload to the iot platform.we can monitor the system on mobile app.

Change-Id: Ia128f04aa362ed6be8cb9af7e7227a1607ae3bd4

[Detail]
remove duplicate \r\n in haas200 log

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
add pthread_mutex_timedlock's declaration

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
Issue description:

Rootcause:

Solution:

Requirement description:

Solution:

[Verified Cases]
Build Pass: <solution list>
Test Pass: <test case list>
Signed-off-by: Nwzhiyuan-nit <wuming.wzy@alibaba-inc.com>

An enum-typed expression is used in a Boolean conditional context. The
enum type does not appear to have a distinguished false (zero) value.

Change the type as int to fix such issue.

[Detail]
fix build issue in debug lastword

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
Debug cli command prints cpu_binded/cpu_num/cpu_exec information on
multi-core cpu.

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
none

[Verified Cases]
Build Pass: <py_engine_esp32_demo>
Test Pass: <py_engine_esp32_demo>

[Detail]
Issue description:

Rootcause:

Solution:

Requirement description:

Solution:

[Verified Cases]
Build Pass: <solution list>
Test Pass: <test case list>

[Detail]
Add README.md

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
Add README.md

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
Add README.md

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>

[Detail]
Add README.md

[Verified Cases]
Build Pass: <py_engine_demo>
Test Pass:  <py_engine_demo>