fmbtgti: beforeRefresh and afterRefresh callbacks on waits

wait, waitBitmap, waitOcrText, waitScreenUpdated and
fmbtandroid.waitText accept beforeRefresh and afterRefresh
callback functions as parameters.
learn: fixed execution time, unit test added

"learn=time" works without multiplier parameter, initial value is NaN,
automatic unit test added.
Merge remote-tracking branch '01/devel' into for-devel