Tempo synced Delay Plugin

I have been working on a native delay plugin. It makes use of the TempoSycnKnob for both the delay time, and the lfo time.

first pull request ever !!! please let me know if I have done anything  wrong..
further optimization could be made by moving the call to the value() outside the loop...
Save the value from m_delayTimeModel.value() to a const float right before the frames loop, then use the const float as argument in setLength... this way there's n less calls to value(), non-inline function calls are overhead so best to minimize them.
(No need for the f parameter in value(), that's deprecated and doesn't really work)