R1:4f3fafd2e91a

Create a basic meme dialog

Summary: Simple dialog for creating memes. We can add more features (typeahead, selection thumbs, preview) later.

Test Plan: {F29815}

Reviewers: DeedyDas, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T2353

Differential Revision: https://secure.phabricator.com/D4557