Pull the remote feature branch before deliver

This fixes an issue where if you ran `deliver` and your local branch
wasn't up-to-date with the remote branch, the commits on the remote
branch would not be included.

That's the worst case scenario. This will prevent it from happening
again.

Closes #39

LGTM given by: @codenamev

Squashed commit of the following:

commit f435d749ac91ad7c9f1f57fdd1eeb5f5c7916e86
Merge: 0d70369 7553e36
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Fri Jul 12 09:49:56 2013 -0400

    Merge branch 'nh-pull-feature-branch' of github.com:reenhanced/gitreflow into nh-pull-feature-branch

commit 0d7036936fda71ea577a2a1954fe41bbd1764909
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Fri Jul 12 09:49:42 2013 -0400

    Version bump for bugfix

commit 7553e363595cb0c180f34467e3175428376c8ac6
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Fri Jul 12 09:46:47 2013 -0400

    Update README.rdoc

commit 89f66837c4a361e46dc7df79e221b454a3c862e1
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Fri Jul 12 09:40:07 2013 -0400

    PUll the remote feature branch before deliver