- libavcodec issue
- some decoders alter AVCodecContext width/height values, in a wrong way
- eg. in issue 2815, vp6f decoder changes these values, resulting in distorted / invalid frames
- this patch forces default AVCodecContext values

Manager verison incremented;
Additional constatnt for library intialization added;
Documents updated.

cmpEps replaced on cmpEps2 to reduce code dublication;
Constants for cmpEps return values added.

range in calcHist() changed from [0,255] to [0,256]. Otherwise, it won't count pixels with value 255. It can be verified taking sum of histogram values and checking it with image size.

* removed OpenGLFuncTab, now extensions are loaded internally
* added support of GlBuffer and GlTexture2D to InputArray/OutputArray
* added ELEMENT_ARRAY_BUFFER and PIXEL_PACK_BUFFER targets
* added copyFrom/copyTo method for GlBuffer and GlTexture2D
* removed GlFont
* removed pointCloudShow
* removed OpenGLCleanCallback
* added Access parameter to GlBuffer::mapHost
* added autoRelease parameter to all create methods

See http://sourceforge.net/tracker/?func=detail&aid=3484857&group_id=38414&atid=422030

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