Removed redundant homebrew python path.

The homebrew python used to require `/usr/local/share/python` to be on the path, so that installed plugins (through pip) could be accessed on the path.

This has since been changed, and is no longer required. Python modules (eggs) are now installed straight into `/usr/local/bin`
Upgraded to new python version of Powerline.
Installer can now install essential homebrew apps.

The installer will now give the option of installing the following essential homebrew apps:
 - hub
 - python (2)
 - macvim
Automatically install Vundle Bundles from installer.

The installer now offers to install Vundle, and all of the Bundles specified in .vimrc.