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

This reverts commit 2c534ee8.

Revert "Revert "ENH: Mantis-1355 : Apply patch to set OTB_APPLICATION_PATH environment..."" this fix was fine

This reverts commit 562ddd8d.

The fix consists of:
- Quicklook and Histogram widgets:
    * More flexible min/max sizes
- Color Setup Widget
    * Remove uninformative label to save vertical space
    * Change size policy to Minimum
    * Add 9px margin for look and feel

Revert "ENH: Mantis-1355 : Apply patch to set OTB_APPLICATION_PATH environment variable in monteverdi desktop file"

This reverts commit cb38ea6f.

Revert "BUG: prevent tinyxml header to define DEBUG on windows, conflict with itk::LoggerBase::DEBUG"

This reverts commit 507c6dc2.

Terminate MPI before the end of the main instead of the destructor.
Also clear FFTW threads at the end of DoExecute() not in the destructor.