Start of work to let user select repos
* Show repos at the top and let user edit existing repo name
* Refactor out edit-in-place functionality into EditableView and use it in queries and repos
* Break Repos and Issues into separate modules
* Break FocusManager into its own module
Remove hardcoded repo, let user set it on first launch
Hide query box when no repos are specified
Add plus button for adding multiple repos to search. Fix a few bugs. Switch out icons of uncertain provenance for attributed icons. Add LICENSE.