merge simulator for linux to master branch

these version can work very well under 32bit-linux distribution. 
And bsp/simlinux is merged into bsp/simulator.
Now, simulator for linux support:
1. finsh
2. elm fatfs
3. uffs
4. RTGUI

TODO:
1. jffs2
2. dfs_linux
3. lwip
4. app module (simulator for windows not supported yet)