🎉 New Features: Tips for citation data and more

It's almost 2019 and we've got some big improvements on the way (spoiler: notecards is one of them). For now though, here's a couple of smaller updates.

First up, be prepared to see helpful tips when entering data for each citation. These include pointers for finding specific pieces of information, and examples of the data you should be entering. We've also included some warnings to make sure you're capitalizing words that should be capitalized, and lowercasing those that shouldn't.

We've added a couple of quality improvements too -- you can now select multiple citations and then drag them to other projects, or delete them all in a single click.