UINavigationBar and UI-states implementation refactor

[naldikt]

• Added more UI-tests samples.

• Welcome UINavigationBar+NXSS

• Changed the way applyNXSS is done on classes:

• instead of having applyDeclarations() call super's, it's no localized to each class (private definition)
• now each applyNXSS_* must apply internally while still calling super.
• UIButton now uses setTitleColor(forState) and setTitle(forState) when applying styles with states.