Allow branch specific fetching / (pulling updates into a branch without switching to it)

This would be especially useful with Git Flow. If you're working on a feature branch, and want to finish the feature and merge back to develop, there's a high chance that someone has made changes to the develop branch, which means your develop branch is out of date. To be able to finish the feature, you'd have to switch to develop, pull from the origin, switch back to the feature branch, and then then finish the feature.

It would be much better if you could just make your develop branch pull the latest updates without having to switch back and forth to it. Luckily, it's very trivial to do with git. Just run a fetch command!

> git fetch origin develop:develop

This would fetch the latest changes from origin's develop into your own.

Ideally, the git flow commands should do that automatically (or better yet - present a prompt for that), but I'd love it if I had a "Fetch from origin" option in the context menu of a branch as well!