Added a button dropdown component with dynamic properties
Added basic tests for the new component
Added the test to the include list for QUnit
Updated README to document the new dropdown component
Small correction in the YUIDoc comment
Changed value of href attribute to a hash
Changed template/layout concat to use array var instead
Corrected typo in ButtonDropdown class
Changed to using defaultTemplate only, as in ModalPane
Updated tests and added tests for adding/remove elements from the dropdown
Added comments to the two new tests
Merge pull request #84 from Wildhoney/button-dropdown-component

Implemented the ButtonDropdown component