SADXModLoader/CMakeLists.txt: Undo hard-coded bass library; s/mcrecover/SADXModLoader/

The hard-coded bass library was a temporary adjustment to get
the DLL to (somewhat) compile with MinGW.

The "mcrecover" reference is a leftover that I forgot to change.
SADXModLoader/stdafx.h: Added ninja.h and SADXModLoader.h.
libmodutils/: Split several files from SADXModLoader into a separate library.

These files aren't actually used by SADXModLoader, but may be
useful in mods designed for use with SADXModLoader.