Remove pkgfile and other cleanup/maintenance

This pull request resolves #52 and also adds a lot of other misc. cleanup, especially in the PKGBUILD files and the scripts directory.

PKGBUILD-git is now pacman 4.1-compatible and fixes a broken build introduced by commit 822abf4. Please update the AUR package 'pkgtools-git' using this new PKGBUILD.

After merging, please tag a new release.