spacing
Add support for default values
Merge branch 'default_values' of https://github.com/opsb/ember-orbit
Rename `data` param for `normalize()`
Expand comments in test
Allow custom source/store classes to define `orbitSourceClass`

If `orbitSourceClass` is obtained through the _super chain, its wrapped
function needs to be dereferenced. These gymnastics are only necessary
when retrieving a *constructor* function from an Ember  class hierarchy.
Otherwise, `superWrapper` "just works".

[Fixes #5]
Allow source to be initialized with an instance of an orbit source