[ubuntu] Added various function tests
[ubuntu] Added various function tests

* Added implementation of `cvGoodFeaturesToTrack`, `HoughLinesP` and `cascade.detectMultiScale` (works better than the one in the separate file).
* Implemented HSV mask to volume filter to smoothing and thresholding to get a decent skin filter.
* Face detection still lags, but it is meant to work on a background thread or queue.

uroboro/DIP,uroboro/DIP,uroboro/DIP,uroboro/DIP,uroboro/DIP