Major modifications

- Action.pde: A user can now bind a function to a control depending of
the type of event
- Dialog.pde: Support for dialog windows
- Frame.pde: A frame now holds all the controls, including dialog
- Gradient.pde: Supports vertical gradient
- Shadow.pde: Supports drop shadow
- Textfield.pde: Simple implementation of textfield
- Textured Controls: Redrawn control elements based on the vue UI Kit
(http://webdesign.tutsplus.com/freebies/free-site-elements/exclusive-psd
-freebie-vue-ui-kit/)
-  Tooltip: Basic tooltip when control is hovered