They were blocking each others' input unnecessarily.
Implements IHasAccentColour for conformity to rest of project. Also fixes a nullref when opening the login menu.
# Conflicts: # osu.Game/Graphics/UserInterface/OsuPasswordTextBox.cs
Fixes them not working at all, too.
Uses GetContainingInputManager instead, as per framework changes.
This also - Renames TextAwesome to SpriteIcon. - Removes the default size of "20" from SpriteIcon (now defaults to the underlying texture size).