Squash, edit, and merge in Gio's refactor

MP2E's notes: source files are lowercase, AUTHORS and LICENSE are now included, too

Refactoring; a little of this, a little of that
Fixed CMakeLists.txt; WadGen will now build.
Create doom64.wad and doomsnd.sf2 with lowercase filenames.

Uppercase is unusual and inconvenient to work with on Linux.
Merge pull request #2 from chungy/master

Create doom64.wad and doomsnd.sf2 with lowercase filenames.
Use Quasar's strupr and fix mingw-w64 compile

Note it still crashes
Rewrote Wad_CheckLump to be more portable

Now works full on MinGW-w64 and w32! Special thanks to Quasar
Merge branch 'master' of github.com:MP2E/Wadgen into MP2E-master

Conflicts:
	.gitignore
	AUTHORS
	CMakeLists.txt