added basic Edit Text / Add Translation buttons to verseControl menu
translate options shows only when English is unavailable
Merge remote-tracking branch 'refs/remotes/Sefaria-Project-upstream/master'
Copy and delete source sheets (reverse-merged from commit 1f3fbe591423627208bc2862140c8ea2396afb02)
modifications to improve edit/translation of verses.
restore reverse-merge, and put back to normal
Turn 404 page black
Add placeholders to 'add translation'; add login prompts; restore new sheet check on copy option
Merge branch 'master' into pull55