Remove deprecated action lookup as methods on controller.

The older lookup in the root of the controller has been deprecated
since late-2013, and is a frequent cause of annoyance for newcomers.
This PR removes the deprecated lookup completely.

This has been discussed with the full core team.
Merge pull request #5347 from rwjblue/remove-deprecated-controller-action-support

Remove deprecated action lookup as methods on controller.
Unify observer/observes implementation

This is similar to the implementation of FunctionPrototype.property /
Ember.computed.  Now when the Ember.observer function is modified the
function prototype will already of the correct behavior.
Merge pull request #4821 from rondale-sc/unify_observer_observes_implementation

Unify observer/observes implementation
Cache length in observesBefore for loop
Use one variable assignment per declaration.
[FEATURE ember-handlebars-compiler-ast-to-precompile] Allow precompile to accept an already existing Handlebars AST

[FEATURE pass-ast-to-precompile] Adding feature flags

[FEATURE pass-ast-to-precompile] Changing flag name
[BUGFIX] fillIn helper should take context into consideration
Merge pull request #5352 from teddyzeenny/fix-fillin

[BUGFIX] fillIn helper should take context into consideration
Merge pull request #5341 from chadhietala/pass-ast

[FEATURE pass-ast-to-precompile] Allow precompile to accept AST
Merge pull request #5350 from cibernox/fix_cache_length

Cache length in observesBefore for loop
Add missing tests for Ember.DAG

I am not sure sure hoy to tag fixing the absence of tests.
Merge pull request #5354 from cibernox/test_ember_dag

Add missing tests for Ember.DAG
Merge pull request #5351 from rwjblue/single-line-var-declarations

Use one variable assignment per declaration.
Use jscs for style checking.