Change test-cluster plugin to misc plugin

Current uses:
- test cluster warning and student lockout
- adding hostname of app node that handled the request to the ENV var
  (JS global)

Fix file-encoding issue with test_cluster plugin

1. Loads the plugin properly to avoid the file-encoding issue.
2. Renames the plugin to aaa_sfu_misc to:
  a. resolve load-order issue (it must load before the recaptcha plugin)
  b. plugin can be used for other misc injections and stuff

move actual code to lib/test_cluster and require it in init.rb

rename plugin to aaa_sfu_misc

Plugin needs to load before the recaptcha plugin because Rails.

add APP_NODE to JS ENV var
Merge pull request #130 from grahamb/canvas-236-test-cluster-plugin

Change test-cluster plugin to misc plugin
add fix for new conversations toolbar appearing under rainbow bar

add utility functions

add fix for new conversations toolbar appearing under rainbow bar
remove duplicate comment
Merge pull request #131 from grahamb/discussions-top-fix

add fix for new conversations toolbar appearing under rainbow bar
Make Course form compatible with Backbone 1.0.0

In Backbone 0.9.9, the "request" event was added to Backbone.sync, so
the Collection#fetch override to trigger "request" is no longer needed.

In Backbone 1.0.0, the default updating mechanism after a fetch no
longer triggers "reset". Use the "sync" event instead.
Merge pull request #132 from va7map/canvas212-backbone_1_compat

Make Course form compatible with Backbone 1.0.0