SAGA: Fix odd memcmp() conditions, as reported by clang

Thanks to LordHoto for pointing those out - they followed the incorrect
paradigm of previous code
MT-32: Sync with the latest changes in munt

This syncs our code with munt commits 258cd89 and 17b40a6
CREATE_PROJECT: Fix a typo in the help-message (--codeblocks)
NEVERHOOD: Fix save slot selection

My initial suggestion to fix the issue was made in 163023a, which broke
the save slot selection logic. The actual save slot selection problem
was fixed in commit 2ca36ab
NEVERHOOD: Fix typo in variable name
NEVERHOOD: Add a new console command, "playsound"