Changed clone() interface of EstimationFilter, to be more clear in ownership context.
Track::ApplyMeasurement method implementation.
Proper initialization of KalmanFilter introduced to estimation::KalmanFilter.
Added ugly KalmanFilter preinstalled setup (as a separate include file).

It's very ugly solution, but for now it's only needed for fast testing purposes.
There will be different solution provided, when needed for testing.
Implementation of Track::isTrackValid method.

Unit tests included.