Add `helm-init` script.

`helm-init` clones a repo and creates a branch locally & remotely so we can
begin work on a ticket.

It mimics the git clone command, but we only the master branch and the branch we
need. And by using git init, we set up hooks automatically if `init.templatedir`
is set in the .gitconfig
git commit hooks. they are a work in progress/shell learning
git: set push default to "current"

The servers at work run an older version of git and it's really not
worth the hassle to keep on using "simple". At least not by default when
the only person running a new git version is me.
bash: fix path to git-prompt.

Use $HOME when sourcing git-prompt because ~ isn't expanded (?).
vim: vundle seems to work with 7.2

Vundle works with vim 7.2. Found out while checking the NeoBundle page.
If it breaks, I can always try NeoBundle without much hassle.

This is great since the servers at work run 7.2
fix: track the remote branch

I am dummy. Track the remote branch.
vim: update vundle
update install script
helm: only check the remote branch if a branch is given

Only check for the remote branch if one is given. If not, don't
checkout any branches.
helm: refactor; make it pretty; fix: don't create a branch if it isn't given.

- Fix: Only checkout master if a branch is not given. Do not attempt to create
  an empty branch.
- Added utility functions to `helm-lib`. These help to make the app a little
  prettier.
- Moved git utility functions from `helm-init` to `helm-lib`