Add deprecation for old usages of cachable and readOnly in CPs

* Passing opts.cacheable to the constructor of ComputedProperty is deprecated
* Passing opts.readOnly to the constructor of ComputedProperty is deprecated
* Invoking `cacheable` in a computed property is preprecated.
* Invoking `readOnly` with aany params in a computed property is deprecated.
* Make InjectedProperty inherit `readOnly` from CPs prototype
[BUGFIX beta] Only register core libraries once.

In Ember CLI (and in our own test suite) many Ember.Application
instances are created.  This prevents each test from triggering
a warning that the library has already been registered.
Add HTMLBars version of makeBoundHelper.

Much simplified. Behold...
Deprecate Ember.Handlebars.makeBoundHelper.
Deprecate Ember.Handlebars.helper.
Merge pull request #9750 from rwjblue/htmlbars-make-bound-helper

Add HTMLBars version of makeBoundHelper.
Add Stream.prototype._label.
Refactor HandlebarsCompatibleHelper to avoid preprocessArguments.
Merge pull request #9755 from rwjblue/label-streams

Add Stream.prototype._label and remove HandlebarsCompatibleHelper.prototype.preprocessArguments.
Use Stream.prototype._label for Handlebars compat makeBoundHelper.
Set Stream._label in constructor.
Merge pull request #9756 from rwjblue/update-compat-make-bound-helper-to-stream-label

Use Stream.prototype._label for Handlebars compat makeBoundHelper.
Merge pull request #9757 from rwjblue/set-stream-label-in-init

Set Stream._label in constructor.
Use Stream.prototype._label for HTMLBars {{unbound}} helper.
Merge pull request #9758 from rwjblue/htmlbars-make-unbound-use-label

Use Stream.prototype._label for HTMLBars {{unbound}} helper.
HTMLBars compiler plugin for {{each .. in ..}}
HTMLBars compiler plugin for {{with .. as ..}}
Bump HTMLBars version.

Changes:

* Robust tracking of quoted and unquoted attributes.
* Refactor AST to always treat sexprs as an array.
* Add compiler plugins.

Compare view:

https://github.com/tildeio/htmlbars/compare/v0.1.11...v0.1.12
Merge pull request #9759 from emberjs/htmlbars-plugins

Use HTMLBars plugin system to transform non-standard templates.
Remove types in HTMLBars helpers