Add input sequencing support

[fa1k3n]

The idea is to have a list of inputs that are automatically switched between every X seconds.
Three types of switching

• Single shot - Every camera is switched to in order according to sequence list
• Bounce - As single shot but when last camera is done then the sequence goes back in reverse ; 1-2-3-4-3-2-1.....
• Random - A random camera is selected from list, a selected camera can never get active again until all cameras in list have been active

In should be possible to loop all types. When looping, each switching type will restart from the beginning when it is completed. The Random switching type will re-randomize the inputs before restarting.