Make computed properties remember the last value of this.

It stores the value of this from the last time the computed
property was evaluated.

It allows notify to re-evaluate the computed property using the
correct value for this, instead of the global object. This is
particularily necessary when a dependency notifies.

It allows a single computed property to be applied with different
values of this. This will be useful particularily to apply the
same computed property to each object in an array.
Defer property evaluation to data binding function.
This way properties can be applied with different values of this.O
Add foreach and do data bindings
Use joga properties instead of direct objects for consistency sake
Fix typo
Use divs instead of spans when nesting elements in test.
Nesting elements inside spans is not legal html.
Add tests for creating bindings from regular objects
Fix some jslint errors