GXemul Code2

nbjoerg on #GXemul (FreeNode) noticed an easy way to trigger an unhandled case in memory_sh.cc. Hopefully this is the correct solution.

Use exit(0) instead of exit(1), per Andreas Ehliar's recommendation.

Remove callgrind and cachegrind output files on make clean, and adding a comment about using valgrind to the configure script.

Minor update of the guest OS documentation.

Updated TODO.

Bogus hack to machine_evbmips.cc to let RTEMS print some boot messages (again?) for mvme5500.

Adding configure script detection of -Wextra -Wno-unused-parameter -Wcast-align.

Running 'make test' will now treat memory leaks as test failure (in debug builds only). Also fixing a memory leak (in an ugly way).

Adding check for -Wnon-virtual-dtor.

Fixes to allow build using GCC's -Wshadow. Adding detection of -Wcast-qual and -Wshadow to the configure script.