feat(mvc.$): update methods for better backwards compatibility

[kumilingus]

Description

Improve the mvc.$.fn methods not to introduce breaking change unnecessarily

• fix html() method typos
• return this to allow chaining
• add toggleClass(), prop(), height(), width(), children(), clone()
• add other property method wrappers such as val(), scrollTop()
• add animation() and stop()
• add offset() and position()
• add a few tests