downcase default locale; enforce locale validation
add 'en' as default available locale (required by some third-party libraries)
Add extra conditional in options_for_locale_select (pass tests with 'en' in available_locales)
Merge pull request #564 from code-dot-org/downcase_default_locale

downcase default locale; enforce locale validation
Merge branch 'finished' of https://github.com/code-dot-org/dashboard into finished
Automatically built.
Automatically built.
Comment out two of the three android browsers from automated UI testing.
Merge branch 'finished' into delivered