Add way for plugin to specify label for quick open
Merge with master
Made optional arg handling more consistent in Quick Open plugin API
Clean up various dialog label code paths. Don't set the label before the first call to filter.
Allow plugins that don't care about language to work when no documents are open
Merge branch 'master' into nj/QuickOpen-label
Code review cleanups
Merge pull request #3059 from adobe/nj/QuickOpen-label

Add way for Quick Open plugin to specify label for quick open, make some plugin args defaultable, and allow language-agnostic plugins to run when no files open