CoInitialize/CoUninitialize in VFW classes (#8112)

- fixed returned compactness value
- added centers drawing to the example app
- added compactness test

 - brush up v_reduce_sum of SSE version

Add wrappers for load functions for DTrees and Boost classifiers

fix wrong conversion in estimateAffine2D* functions

Wrappers for load methods of EM, LR, SVMSGD and Normal Bayes Classifier

test with integer points to cover conversion bugs.

functions support points to have other datatypes than floats.

* fix bug in coversion that overwrites src points with dst points

 - make sure SIMD optimization works even when AVX is not available