Update Handlebars metadata to not require "escape" and use utils.

The most recent release of Handlebars makes it so we no longer have to
re-implement the "handlebars-utils" module.
Import Handlebars.js @ 1.0.rc.2.
Update Handlebars test to ignore empty-string test.

The Handlebars.js project changed the meaning of `isEmpty()` to return
`true` for empty strings. Since we no longer re-implement the
"handlebars-utils.js" file, this ignores the one failing test.

https://github.com/wycats/handlebars.js/commit/5f56d6
Update Handlebars documentation for upgrade.
Rename events: loading->beforeLoad, loaded->load
Consolidate Tree.Node extension modules into Tree extension modules.
Rename openable methods: toggle->toggleOpen, toggleNode->toggleOpenNode
Rename _fire() to _fireTreeEvent().
Move AOP bindings to the initializer and add tests to cover them.
Use more unique AOP method names to avoid collisions.
Update API doc module tags.
Add Handlebars test for arrays as context objects.
Fix #2533116
Fix #2532025
Fix #2533101
Merge branch 'trac2532025' into sprint5bugfixes

Merge branch trac2532025 into sprint5bugfixes.
Merge branch 'trac2533116' into sprint5bugfixes

Merge trac2533116 into sprint5bugfixes.
Merge branch 'trac2533101' into sprint5bugfixes

Merge  trac2533101 into sprint5bugfixes.
Fix #2533124
Updated category axis unit test for trac2533124.