Add IPP erosion and dilation
Add sort_by_key for oclMat.
Most codes are ported from AMD's Bolt library.
Four methods are implemented:

SORT_BITONIC,   // only support power-of-2 buffer size
SORT_SELECTION, // cannot sort duplicate keys
SORT_MERGE,
SORT_RADIX      // only support signed int/float keys
refactored generalized hough (both CPU and GPU):

removed set/get methods from Algorithm (implement owns)
removed GHT_* enumeration
gabor filter docs Bug#1894
ref in inpainting docs
pydocs for cv2.findTransformECC
added gridTransform/gridCopy overloads for GlobPtrSz
added globPtr for GpuMat
added cudev::GpuMat_<T> support to Input/Output arrays
rewrote matrix operations with cudev module
Removed CV_EXPORTS from all template classes (that I could find).

It doesn't make sense to export template classes, since there's no way
the user can learn that it can import them. In fact, it is somewhat
deleterious, because every module will export every instantiation
that it uses, but doesn't inline.
Add IPP mean and sum functions
Fix build errors
epilines pydocs
Some changes in sum and mean functions
morphologyex docs bug#2169
imshow docs improvement bug#2490
Some modifications to sortByKey API.
Add documentation.
Fix doc build error.
Some changes in erosion and dilation functions