Merge pull request #252 from nanan9177/feedback_collect

Feedback collect
teachers can remove students, fix spelling, fix email subject, add confirm before remove, redirect to localhost on signout for development environment
Merge branch 'master' of github.com:code-dot-org/dashboard
clarify email text
temp fix for localization problem with missing param
Quick fix for sign up form. Need to investigate more on password placeholder.
Merge pull request #254 from nanan9177/blockly_fix

Quick fix for sign up form. Need to investigate more on password placeho...
Updated all blank fields except for password fields.
Merge pull request #255 from nanan9177/blockly_fix

Updated all blank fields except for password fields.
Added password text field.
Merge pull request #256 from nanan9177/blockly_fix

Added password text field.
tweak string to say 15 instead of 10 students
Calling og:tag only if level_source controller is calling the page.
Moving show image and generate image to level_helper.
Hide the solution page link on solution page.
Add optimizely on production
Merge pull request #257 from nanan9177/blockly_fix

Calling og:tag only if level_source controller is calling the page.
Updating level source id for ideal solution.
Merge pull request #258 from nanan9177/blockly_fix

Updating level source id for ideal solution.
Adding add hint flow to the add hint page.