It is designed for 1D vectors only

This is at least useful when using an SVM one-class linear classifier, so there are valid use cases.

* expose 2 extra methods from ml::TrainData: getNames() and getVarSymbolFlags(). The first one returns text labels from CSV (if the data has been loaded from CSV); the second one returns a matrix of boolean values; its n-th element is 1 iff the corresponding column in the CSV uses symbolic names, not numbers.

* check that the dynamic_cast succeeds

2. fixed parsing of "cat[range_spec]ord[range_spec]" type specification string when using ml::TrainData::loadFromCSV(). Thanks to A. Kaehler for reporting it

Update to allow loading data from a .csv file that only contains training samples values and not the associated responses. To allow this behavior, function must be called with parameters ResponsesStartIdx <= -2 and ResponsesEndIdx = 0

- added test for loading legacy files
- added version to new written models
- fixed loading of several fields in some models
- added generation of new fields from old data

"int * CvMLData::sample_idx" was not freed

1. someMatrix.data -> someMatrix.prt()
2. someMatrix.data + someMatrix.step * lineIndex -> someMatrix.ptr( lineIndex )
3. (SomeType*) someMatrix.data -> someMatrix.ptr<SomeType>()
4. someMatrix.data -> !someMatrix.empty() ( or !someMatrix.data -> someMatrix.empty() ) in logical expressions

initial commit; ml has been refactored; it compiles and the tests run well; some other modules, apps and samples do not compile; to be fixed

This reverts commit 4d36be87.

Conflicts:
	modules/ml/include/opencv2/ml/ml.hpp
	modules/ml/src/data.cpp

This reverts commit a8c5e356.

Conflicts:
	modules/imgproc/src/imgwarp.cpp