1. Cleanup unused code in startup.c.
2. Init MMU before init INT contoroller for mapping vector table to visual address 0x0
3. Remove unused section in link scripts.

1. Combine code for IAR and GCC in file mmu.c and cpuport.c
2. Remove remap code in start_xxx.S. User should config MMU to map vector table to visual address 0x0

[bsp][stm32f03x] Modify build config to reduce code size for Travis CI

2. [bsp][sam9260] Remove unused ld file
3. [bsp][sam9260] Add J-Link debug scripts

1. [bsp][sam9260] Fix the bug that auto reset after boot 20s. Disable watchdog in rt_lovel_level_init function.
2. [bsp][sam9260] Modify SCONS scripts to support IAR tool chain.
3. [bsp][sam9260] Move link strips in to folder link_scripts.
4. [libcpu][arm926] Add copy right to source file and format code.

Fix a regression on 62a0172d.

The old `--keep` parameter for Keil is wrong. RTFM of Keil and get it
right.

[DFS] fix the NFS link issue

[tools] Add package.json as building script.

memheap: check the USED bit in rt_memheap_free

This will ease the debugging of double-free bug.

修正rtt-root位于其他目录时计算目录错误的bug

Use svg instead of png to get better image quality

[DeviceDriver] stm32: Remove explicity clear of RXNE flag

According to STM32 Manual, the USART RXNE flag will be clear automatically after
read to the USART_DR register[1], so the call to USART_ClearITPendingBit is
unnecessary.

[1]: See RM0090 Reference Manual p.992, Bit 5

生成vs文件时将区分编译目录，防止同名的源文件不能编译的情况

update nrf51822 in bsp

[BSP] add nRF51822 BSP.

[DeviceDriver] Fix inverted logic on SConscript

Remove dataqueue/pipe if not enable RT_USING_HEAP, supply the missing `not`.

[bsp]stm32f107/.uvprojx:fix mcu type error