Better git diff

The output of git calls, e.g. git diff, can be improved. Instead of only showing changed lines it can highlight the parts of a line that actually changed. See this thorough post.

To use the diff-highlight program (already bundled with git!?) do the following:

1. add the program to be available from your $PATH, e.g. ln -s ~/.local/bin/diff-highlight /usr/share/git/diff-highlight/diff-highlight
2. edit your .gitconfig:

   $ vim ~/.gitconfig
   # ...
   [pager]
     log  = diff-highlight | less
     show = diff-highlight | less
     diff = diff-highlight | less