This workaround is added to avoid a crash in application when build
is made with RelWithDebInfo which is caused by a
boost::archive_exception impossible to be catch.
This workaround break the compatibility with shark model direct
read/write.
It is still possible to read old RF model from OTB.

SampleSelection can now be used without input vector data.

When only image is provided to the application a default vector
corresponding to the image envelope is generated.

All Supervised and Unsupervised Classifier should be declared and stay
in Supervised/MachinLearningModelFactory since multiple application
depend on it.

Use inheritance with otbTrainImagesBase to create unsupervised
composite application.

Create a common class with template to perform Supervised classification
(same as otbTrainImagesClassifier) or Unsupervised.

Add the ability to specify Supervised or Unsupervised classification

Inherit TrainVectorClassifier from TrainVectorBase and use Non-Virtual
Function Idiom to provide common behavior for Unsupervised and
Supervised classification.

Move commons files for both supervised and unsupervised into
LearningBase Module.
Also update Test and includes.

This reverts commits:
3d4ab1ff
2dc562e6