Bump version to 1.0.0.
Set automake foreign flag.

This gives us a little bit of leeway in file naming (e.g. README.md
instead of README).
Remove generated Doxyfile.
Rename library from SDL_Pango to SDL_PangoDraw.
Ignore dist files.
Use pkg-config to find SDL.
Fix ref to renamed configure.ac.
Install .gitattributes.
Modernize configure.ac a bit.

Also using m4_eval for Libtool versioning math instead of running eval.