Extend object properties instead of overwrite

For prototype properties that are objects, such as "events" in a View or "defaults" in an Object, is more useful to mix with the parent's version instead of overwrite them.
Demo for extending models and views properties

This is an example of extending a Model's defaults hash and View's events hash.
Fixes #20: Added AMD definition for Backbone-super plugin. The code is based on Backbone AMD definition.
Deleted merge change denied
Removed unnecessary references in module definition.
Added demo using require.js
Merge pull request #21 from jvitela/master

Fixes #20: Added AMD definition for Backbone-super plugin.