Dev/ewma2

This shows how the EWMA2 filter would look with a dynamic dt using a timer.

The advantage of using dynamic dt is;

1) if the update interval varies because of system load/whatever, then the amount of filtering will not vary.
2) if tracker.cpp's update behavour/interval/whatever changes, then the amount of filtering will not change.

Note this is based on unstable, not your ewma dev branch which seems to include a fair bit of debugging stuff. I don't have an environment setup yet that can make ui changes so the settings are all unchanged. Once I get Qt5 Designer running I'll put together some UI changes for the baseSmoothing, dynamicSmoothing settings we discussed.