add MSVC components initialization support

MSVC handles section setting differently from other compilers. It seems that there is no way to add an abstract layer of such issue. The SECTION macro in rtdef.h is hard to adopt to different compilers.

This is a RFC rather than a serious "request" since I just test it on RTGUI. Although it compiles on MDK, I haven't tested it on the board neither tested compiling with GCC. Please test it on the board with various compilers before merging. If there is any problem, please comment here and I will try to fix them accordingly.