Added some asserts.

Added function makeData() in test_svmsgd.cpp.

Also fixed documentation, refactored sample.

related to issue 4969
fixes issue 5891
fixes issue 5922

Someone forgot to wrap the load function for SVMs in the
corresponding ml python module. Fixed that.

Update docs according to PR #5127

misplaced CV_WRAP statement lead to not exposing EM::getCovs() to python/java/matlab wrappers

add a CV_OUT to return the covs properly

2. Algorithm::load/save added (moved from StatModel)
3. copyrights updated; added copyright/licensing info for ffmpeg
4. some warnings from Xcode 6.x are fixed

REG_NONE defined in ml.hpp conflicts with defined in Winnt.h

- fixed one BiB record
- moved algorithms overview to separate page
- added docs for some enumerations
- fixed some small documentation errors

Removed the "FileStorage::FORMAT_XML" to generalize format of the String
model.

Re-edited the documentation again.

Attempting to re-editing the documentation, to satisfy buildbot error
status.