Add a "First-Over" control policy.

[aarontabor]

Currently, the Myo armband controls can either use a Maximum (only the strongest of the 2 input signals is considered) or a Differential (the difference between the 2 input signals is considered as input) control policy. Another strategy used in practice is the First-Over policy:

• the first of the 2 input signals to exceed a certain threshold is considered as input for a specified time window
• the other of the 2 is ignored until the first signal drops below the threshold
• once the first signal drops below the threshold, repeat

  Proposed Solution

Add a third First-Over control policy, select-able from the System Settings menu.

[aarontabor]

both commits 2c924eff19cc49adccf8dae6d94778311a7dee87 and 9a32819eb0152c6c82fe44dc5dce504820ba686c are a part of this issue fix.