Use newlib in default configuration.
add symbol - '_stext' for lua
add config items for lua
Use USART 6 when system bootup.
Merge branch 'master' of https://github.com/RT-Thread/ART
add arduino library for lua
Merge branch 'master' of https://github.com/RT-Thread/ART
modified build.xml for linux. add mkromfs.py
add description to get rt-thread source code
Change the output ELF file to build directory.
Move sysled into a standalone file.
Add spi initialization in platform.c
Add spi structure initialization.
Add msd driver.

micro sdcard driver on SPI.
add ethernet implementation
remove -Wall parameters
Merge branch 'master' of https://github.com/RT-Thread/ART
Add ART + wifi shield handle in IDE.
Add ART + wifi shield handle.
Update core arudino libraries.