add href and caption for link brick to bricks migration
add basic link brick model
add link brick input form
add link_style to link brick
Merge pull request #39 from screenconcept/features/implement_link_brick

Add Link Brick
Merge branch 'features/use_engine_migration_installer' into releases/v1.0

Conflicts:
	app/views/kuhsaft/cms/bricks/_brick_list.html.haml
add doc for brick methods, rename render_stacked?