created UISlider and UIToolbar NUI renderer
added disabled state to UIButton renderer
Merge pull request #51 from benvium/master

BarButton items not rendered at Retina resolution
Merge pull request #52 from savage7/master

UISlider, UIToolbar and UIButton
Modified naming of Slider *value* properties, added thumb-image, renamed uiSlider variables to slider
Removed Toolbar properties for universal consistency, added shadow-image
Prevented UIButton+NUI from rendering UIBarButtonItems inside UIToolbars
Removed redundant properties and methods that are inherited from UIView
Added support for a handful of properties to TextField
Added roundedRect* methods to NUIGraphics
Fixed a code style artifact in NUIGraphics
Added support for rendering SegmentedControl with +[NUIGraphics roundedRect*]
Rerender size-dependent properties on UIDeviceOrientationDidChangeNotification
Using a UIImageView instead of UIView for TableCell's background-color to improve coverage
Added four new themes, renamed Styles to Themes
Updated podspec to 0.2.4