Use newly added `apply` and `applyStr` helpers elsewhere. Also minify them so they're inlined.

Breakdown of arguments length while running the Ember test suite:
{0: 444966, 1: 62482, 2: 23473, 3: 14270, 4: 3000, 5: 755}
Fix case where args isn't passed

Scumbag @ebryn didn't rerun all the tests before pushing
Revert "[FEATURE composable-computed-properties] Composable Computed Properties"

This reverts commit f34661cb86d1c359fdc2b1cc1b746c649b97e216.

Conflicts:
	features.json
	packages/ember-metal/lib/array.js
	packages/ember-metal/lib/computed.js
	packages/ember-metal/lib/enumerable_utils.js
	packages/ember-runtime/tests/computed/compose_computed_test.js
start moving ember-metal to es6
move even more ember-metal files toward es6!
Finish es6ifying syntax.
Update custom transpile-packages to support many libs
Extra cases where ArrayPolyfills was destructured
Properly expose beforeObserver in es6 module syntax
Beginning to move ember-runtime to es6 module syntax
s/Error/EmberError in computed
ES6 moduleify a bunch of mixins
Convert controllers and computed property macros to es6 modules
Fix syntax error in metal/libaries export
Fix sytax errors in es6 format of ember runtime conversion
Include testBoth helper via ES6.
Move window.Em into main.
Fix typos in get/set import.
Ensure EmberError inherits from Error.
Fix more ES6 imports/exports.