Merge pull request #285 from nanan9177/feedback_collect

Feedback collect
Translations
Initial work on running automated UI tests on many browsers, driven by browsers.json, using BrowserStack.
Turns out learn.code.org has jquery.simulate already available, no need to inject.  Also updated browser list.
Translations
Speeding up the share page.
Added the missing placeholder on sign up page.
Merge pull request #287 from nanan9177/blockly_fix

Speeding up the share page.
Make "free draw" levels show as completed, perfect [Fixes #66023540]
Major UI overhaul of learn.code.org.
Merge pull request #288 from code-dot-org/free_play_dashboard_bug

Make "free draw" levels show as completed, perfect [Fixes #66023540]
enable flappy bird
Merge pull request #289 from code-dot-org/learnui

Major UI overhaul of learn.code.org.
Change 'Sign up' heading to 'Student sign up'.
Update readme with mailcatcher instructions.
Merge pull request #290 from code-dot-org/flappy

enable bird game
Merge pull request #286 from code-dot-org/automate

More BrowserStack automation work
Quick fix for activities with nil level_source_id.
Merge pull request #291 from nanan9177/blockly_fix

Quick fix for activities with nil level_source_id.
Start the CRUD for scripts.