Updated documentation and sample to use the new function API

Added erGrouping function: Find groups of Extremal Regions that are organized as text blocks. Updated sample/cpp to use the complete text detection pipeline

first parameter of createERFilterNM1/createERFilterNM2 is now mandatory. changed the sample program to use the new prototypes

changed default parameters in CreateERFiltersNM{1,2} functions. They are not needed now in the sample example.

Neumann L., Matas J.: Real-Time Scene Text Localization and Recognition, CVPR 2012.

High-level C++ interface and implementation of algorithm is in the objdetect module.
C++ example, a test image, and the default classifiers in xml files.