Style navigation bar the same as the toolbar
Create new black theme

Also make it easier to implement different coloured theme’s
Merge branch 'refs/heads/master' into develop

Signed-off-by: Ross Gallagher <ross_gallagher@rossgallagher.co.uk>

Conflicts:
	CLImageEditor/ViewController/_CLImageEditorViewController.m
	CLImageEditor/ViewController/_CLImageEditorViewController.xib