ADD: Merged svc, abort and irq mode stack.
ADD: Changed MDK project to new format.
FIX: Removed the "static" qualifier of rt_thread_exit().
FIX: Change AT91SAM7X.h to the standard header(AT91SAM7X256.h) of RealView MDK. (not all of them are changed, e.g. sd.c)
FIX: Moved some board-dependent files to bsp.


git-svn-id: https://rt-thread.googlecode.com/svn/trunk@257 bbd45198-f89e-11dd-88c7-29a3b14d5316