GXemul Code2

Minor update.

Adding a mini-howto on how to add components to the framework.

Include some more headers so that the code compiles with GCC/G++ 4.4 20090102.

Clarify what it means to not be cycle-accurate.

Removing the -E machine selection option. -e is the only one that should be used.

memory -> %memory, so that Doxygen does not make links to the memory struct.

Minor clarification of debug vs non-debug vs release.

Moving all thirdparty header files to src/include/thirdparty/.

Removing the userland emulation feature completely (since it was never really implemented).

Make sure that the documentation etc. are in synch before making a release.