Don't allow last host local player to drop out

Caused client to be disconnect and unable to rejoin, but server was still running.
Don't allow networked client to disconnect using dropout command

Make behavior consistent with running a server and consistent disconnect messages (always disconnected, instead of disconnected or dropped out).

Less likely to unintentionally disconnect while adding and dropping local players too.
Free Team Arena fonts/fontImage_X.dat buffer

Caused temp memory to be present all the time, so Hunk_Alloc ignored memory low/high preference.

May have caused other issues as well.
Load base game(s) from gameconfig.txt in fs_game directory

Replace com_basegame and fs_basegame with loading up to 16 game directories from gameconfig.txt in fs_game directory.

fs_game "" is no longer valid. It must always be a game directory, defaults to BASEGAME.

Note: ioq3 server tells client that all pk3s in fs_game are referenced/required, Spearmint now only requires pk3s that are actually referenced.
Note: There is a hard coded fallback for Team Arena.
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	code/renderercommon/tr_font.c