Add btnMovePanelRight: implementation

Using a switch statement, we are checking the parameter (sender)'s tag.
If the tag is 0, the CenterViewController's view is set to the original position within the ViewController.
Else if, the tag is 1, the CenterViewController's view is moved to the right of the ViewController, and he LeftPanelViewController is shown.
Add movePanelRight implementation

Checked to
Add necessary comments to describe the method thoroughly
Code format of movePanelRight

Adds readability
Add movePanelToOriginalPosition implementation

This method contains a UIView animation that returns the CenterViewController's view dimensions back to their original state.
Add resetMainView implementation

Checks to see if LeftPanelViewController is instantiated.
If it is its removed from the view hierarchy and the instance variable is set to nil, and the leftButton's tag is set to 1.