Remove credentials from gitconfig.

Since I am using this in more than one place (namely my job) I would
like my git credentials to be loaded up from the local
configuration. Even though this hasn't affected me (it seems git
actually, correctly, uses the local configuration over an included one)
I would just rather not deal with it.
Add .vagrant and .bundle global ignores.
Slight modification to file testing.
Add pull-rebase alias to gitconfig.
Add support for sourcing profile.

Okay there are two main reasons for doing this:
- I am not a huge fan of adding more things to the list of files that I
need to edit locally on a new computer. If I have already been using a
system I am either going to edit .bash_profile or .profile;
- Since, generally, I assume that I am going to be using my own dotfiles
I will edit bash_localrc for machine specific settings that *may* need
to be run on a non-interactive shell.