Merge pull request #40 from nongxiaoming/master

update the lcd driver to support the new version lcd.
Update libc.c
Update drv_sd.h
Fix TCP_SEG_NUM issue.
Remove RT_LWIP_TCP_SEG_NUM option in rtconfig.h
Format the code style
remove old wifi driver.
update config: add RT_USING_SPI_WIFI
update RW009 WIFI porting.
Merge pull request #41 from aozima/pulls

Pulls
Update README_CN.md
Update README_CN.md
Update README_CN.md
Update README_CN.md
update the wifi example README_CN.md.