Complete refactor (version 2.0?)

Among the many changes:

* Make delegate more similar to a UITableViewDelegate, remove unnecessary methods and code.
* Remove the need for a separated rotatedView, rotate cell's contentView instead.
* Request cells instead of views to delegate and improve cell reuse.
* No more need for EasyTableViewCell or tag constants.
* Do not force hiding scroll indicators, selection types or cell behaviors.
* Support Interface Builder.

Also the library's main utility being horizontal tables, I think vertical support should be deleted and code further simplified.

_Includes changes in #38._