Redefine CPU_xx constants in cv::namespace

This makes them visible from the python bindings
GSoC Python Tutorials
GSoC Python Tutorials

removed white spaces

removed blank lines at EOF

removed duplicate labels
erGrouping now uses a classifier for group validation instead of a set of heuristical ifos.
Updated documentation and sample to use the new function API
Merge pull request #1520 from lluisgomez:scene_text_erGrouping_classifier
Merge pull request #1488 from abidrahmank:py_tutorials
Merge pull request #1477 from nzjrs:python-gethardwaresupport