Added sf- prefix to all selectors attributes
Merge branch 'development' of https://github.com/Sitefinity/feather into SelectorsRefactoring

Conflicts:
	Tests/Telerik.Sitefinity.Frontend.ClientTest/unit/Selectors/pageSelectorSpec.js
Fixed spelling mistake
Fixed failing MultipleTagsSelectorVerifySearchInSelectedTab UI test
Merge branch 'development' of https://github.com/Sitefinity/feather into SelectorsRefactoring