Added ScrollView to Log in scene
Added ScrollView to Sign up scene
Added ViewControllerWithKeyboard class
Refactored classes to use ViewControllwerWithKeyboard

Not everything works smoothly, and some behavior I can't explain. This
needs further work.
Disabled adjusting scroll view insets
Fixed missing legal text
Added resignFromKeyboardNotifications method
Fixed ScrollViews in settings controllers

Previously the view would leave a big margin on the bottom because of
TabBar. To solve this, I first check ViewController if it has
TabBarController, and if it does, I subtract its height from the
keyboard size. Seems to work.
Merge branch 'vc-with-kb' into develop