Add video overlay effects

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Fix deployment warning in unit tests

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Fix integer sign warnings

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Add maximum cap to video capture padding

Signed-off-by: James Tasker <james_tasker1@hotmail.com>
Make video capture rate constant

 - Thread must sleep for longer than the fade runs for
   to prevent arduino board from locking up.

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