Adding a cask for Vagrant v1.4.3.

Squashed commit of the following:

commit e76734d02d096d1a5acf8288d7f12c6cae5436f3
Author: Ben Kreeger <ben@kree.gr>
Date:   Wed Mar 19 12:22:48 2014 -0500

    Ensuring name is correct.

commit 25f3a557f751c037934d35421990fa00c7571543
Author: Ben Kreeger <ben@kree.gr>
Date:   Wed Mar 19 12:21:04 2014 -0500

    Adding a cask for Vagrant v1.4.3.
Switching Vagrant 1.4.3 cask to use SHA256 instead of SHA1.
Merge pull request #169 from kreeger/add-vagrant-143-upstream

Adding a cask for Vagrant v1.4.3.