Add some scripts and updates to some others.

Add:
- git-rewrite-commiter.sh: to rewrite the history with a different
  commiter.
- pipes.sh: an console animation in bash.
- pretty_make.py: an script to make make output prettier.
Modified:
- tb.py: Fix behaviour in falling to execute if not in a repository. It
  is useful when calling tb fetch to create de repo.
- urxvtc-color.sh: eliminating some not so pretty cursor colors from the
  options. Also adding some comments to identify colors.
- vimrc: Formating and add a new function to put characters at a
  specified column. But it is commented out.