Add label control

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Add rendering for labels

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Add label creation to ControlFactory

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Make demo app load controls from a file

Signed-off-by: James Tasker <james_tasker1@hotmail.com>