(fix for edmodo server errors) Appends text/html as an acceptable response type if not present in the HTTP_ACCEPT header. This should stop malformed user agents from generating 'Missing template' errors on pages.
make http header fix specific to Edmodo user agent
add test for edmodo header fix
Merge branch 'master' of https://github.com/code-dot-org/dashboard into edmodo_fix_4

Conflicts:
	app/controllers/application_controller.rb
[Finishes 67575866]: respond with 403 Forbidden instead of server erroring on CanCan exceptions
Fix levels controller test (was failing on multiple test suite runs)
Merge pull request #334 from code-dot-org/edmodo_fix

fix for edmodo server errors
New translation strings.
Translations
Merge branch 'master' of https://github.com/code-dot-org/dashboard into 403-instead-of-500-for-cancan-accessdenied
Merge pull request #339 from code-dot-org/fix_levels_controller_test

Fix levels controller test (was failing on multiple test suite runs)
Drag simulation: add generation of touch/IE10 touch/IE11 touch events instead of mouse events where possible.
jquery.simulate: Convert tabs to spaces.
Merge branch 'master' of https://github.com/code-dot-org/dashboard
jquery.simulate: comments.
Merge pull request #340 from code-dot-org/403-instead-of-500-for-cancan-accessdenied

403 instead of 500 for cancan accessdenied
Merge pull request #344 from code-dot-org/staging

Move "staging" changes forward.
Merge branch 'staging' into test
Merge branch 'test'