Add inline docs for module implementation
Extract Underscore collection mixin
Merge pull request #1113 from jasonLaster/util-collection

Extract Underscore collection mixin
update behavior inline documentation
use the built in marionette extend  for behavior
improve inline documentation for behaviors
Add evented support to behaviors
Add test to ensure execution context
extend region.show to use preventDestroy
tidy up region doc headings
extend region.show to use preventClose
tidy doc headings