Fix order issues with the physical memory manager
Provide better error messages when handling memory aborts
Make printed context information prettier
Generate a linker map file when linking the kernel
Implement create_process syscall and simplify MMU functions

* This commit also includes a simplification of the red-black
  tree finalization code. The functions for freeing data and keys
  are now both specified when the red-black tree is created.
* A new utility function, memcpy_p, for copying data between
  two processes has been added. An extremely low-performance
  basic implementation of the function has been created.
Fix exception return addresses in ARMv7 thread contexts
Improve some debugging messages