Custom Animations - Input Form - Class Extension - GCD Technology

### Features, Animations, Optimal Performance, Class Extension  and GCD

> In this request I had included input forms with cool custom animations using spring animation technology in combination with NSLayoutConstraint manipulation. This was achieved by taking advantage of the NSLayoutConstraint's power for manipulating the objects in which they are attached. A class extension was added for clear visualization of the RBAccountViewController class structure and for organizing the non-native custom methods. GDC (async concurrent technology) was implemented in order to achieve ultimate code performance. Also, minor fixes and code organization.

-- @gchriswill