Remove unnecessary files from source distributions.

Right now GitHub is the main place to track the source and the sources
uploaded to PyPI are just to build with.
I don't need to upload fonts, tools, or tool configs to PyPI.

Author: HexDecimal

MANIFEST.in

@@ -1,8 +1,23 @@
-include *.py *.cfg *.txt *.rst *.toml
+global-exclude .*
+prune .*
+
+include *.py
+include *.txt
+include *.rst
+include *.toml
+include *.md
 
 recursive-include tcod *.py *.c *.h
 
+prune libtcod
 recursive-include libtcod/src *.glsl* *.c *.h
-include libtcod/*.txt libtcod/*.md tests/data/*.pkl
+include libtcod/*.txt
+include libtcod/*.md
+
+prune docs
+prune examples
+prune fonts
+prune scripts
+prune tests
 
-exclude tcod/*/SDL2.dll
+global-exclude *.dll