port StarRating from sbrunot/dojox
refactoring: numStars has been renamed into maximum
tests refactoring to correctly use classes under dui module.
no more event emited on value changed, as widget.watch can be used to
track value changes.
1. remove the _registerEventsHandler function.
2. using dojo/has instead of dojo/sniff.
remove unused attributes.
mutualize _updateStars code between bidi and non bidi widget.
revert mutualization of _updateStars code between bidi and non bidi
widget.
Fix dir calculation for bidi (starting from domNode instead of domNode
parent)
all StarRating widget properties are now stateful.
Fix zeroAreaWidth initialization.
Fix doh tests.
DOH tests added for stateful properties.
StarRating is now using CSS sprites to display star icons.
add bidi support with the WindowsPhone theme.
remove iconUtils dependency (not used anymore).
do not control that zeroAreaWidth is not a negative value.
custom bidi RTL management removed form the widget.
remove tooltip support.