BUG: Set ClipBinsAtEnds to false for histograms in mvdStreamingHistogramVectorImageFilter (Mantis bug #839)

ENH: Applied patch from Otmane Lahlou which group untagged OTB-applications under the 'Unknown' tag.

TRANS: Fixed Qt lupdate 'Qualifying with unknown namespace/class' errors when generating translation file (impacts namespace of localisation strings).

ENH: Better checking of otb::Application output parameters when clicking exec button (more cases OutputImageParameter, OutputFilenameParameter, OutputVectorDataParameter, ComplexOutputImageParameter); ignore parameters disabled or which have a disabled parent).

ENH: Changed message-box when execution otb::Application has finished (replaced Yes/No choice by Ok).

BUG: MANTIS-791 (Accuracy error when using 'Dimensionality reduction'); Missing parenthesis in Scott's forumla used to compute number of bins of histogram lead to a std::bad_alloc.

REFAC: Refactored some exception texts, generalized itk::ExceptionObject catchings to std::exception catchings, cleaned some commented parts.

BUG: MANTIS-785 (itk exception raised when rendering: requested region partially outside of largest region).

BUG: MANTIS-754 (clamped nb of resolutions to 1 when importing images with width or height less than 2 pixels; Hardended and clamped Scott's formula when computing histogram for 1x1 square-pixels and images with single pixel value i.e. case where covariance(i, i)==0).

BUG: Fixing #777 - vcl_abs should NEVER be used on spacing when computing coordinates transforms: most georeferenced image will have a negative y spacing