Reset SideViewController

[michaelcordero]

Presently in SideMenuController.swift, public func embed (sideViewController controller: UIViewController) { if sideViewController == nil { logic... } }
only allows you to add a SideViewController once. My application has a need for resetting the sideViewController to a new instance. Taking away this if condition would solve the problem. Another work around would be to allow the users to set sideViewController = nil, but it has fileprivate(set) access.