basic mingw support for simulator: kernel and finsh
mingw support for simulator: dfs/fatfs
mingw support for simulator: dfs/dfs_win32
mingw support for simulator: dfs/uffs
mingw support for simulator: rtgui
app module support for simlator, first version
Merge branch 'master' of github.com:RT-Thread/rt-thread into sim-module
app module of simlator: rename librtthread.a to rtthread.lib after post-building
app module of simlator: simpliy command of building, now use `scons --def` to create rtthread.def which can used by msvc
app module simulator: add app module test cases
Merge pull request #39 from prife/sim-module

simulator: mingw and  app module support