Added iOS::TabbedBar alias for TabbedBar
Added Ti.UI.Toolbar and Ti.UI.iOS.Toolbar
Make sure iOS::TabbedBar viewHandler behaves the same as TabbedBar
Added viewHandler for Toolbar and iOS::Toolbar

Partially addresses #14.
Merge branch 'master' of github.com:trabian/titanium-backbone
Changed 'underscore' to 'underscorize'

When I saw a pull request related to the 'underscore' method it took me
a moment to realize that it had nothing to do with the underscore.js
library. This name change should prevent similar confusion in the
future.

Related to #15.