re-enable arrow keys functionality

This functionality was originaly removed in order to never use the
arrow keys. hjkl keys are now in my muscle memory so the remaps are no
longer necesary. It will also make my .vimrc cleaner.

By removing it there is always the chance that I develop a bad habit
while using them instead of Vim's intended mobility. But because using
them means moving from my hands home position I'm pretty sure this won't
be an issue for me.

Originaly: http://stevelosh.com/blog/2010/09/coming-home-to-vim/
git commit message formating

In order to write better messages I will follow the standard of 72
characters width columns and make sure I check the spelling before
committing anything.

This single line will do both things every time a gitcommit file type is
detected. English will be the language by default since it's the
language I do my all of my coding.

Taken from:
http://robots.thoughtbot.com/5-useful-tips-for-a-better-commit-message