Add a new class that takes an array of durations and magnitudes.
A magnitude of 0 indicates a pause.
We can consider dropping the VibraRumble class at some point as that
is a special case of VibraPeriodic now however as the feedbacks are
encoded in the themes let's make sure VibraPattern is good API before
deprecating VibraRumble.
Signed-off-by: Guido Günther <agx@sigxcpu.org>
