1. someMatrix.data -> someMatrix.prt()
2. someMatrix.data + someMatrix.step * lineIndex -> someMatrix.ptr( lineIndex )
3. (SomeType*) someMatrix.data -> someMatrix.ptr<SomeType>()
4. someMatrix.data -> !someMatrix.empty() ( or !someMatrix.data -> someMatrix.empty() ) in logical expressions

Conflicts:

	modules/core/src/stat.cpp

if `Scalar:all` is used, Mats with 5+ channels cause errors

Because apparently I love running performance tests for debug builds.

That way, core/internal.hpp doesn't have to depend on cvconfig.h, which we
don't ship.

Namely, normalize their names to a common convention and remove useless text
from their values.

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

added COVAR_ and SORT_ enums to core.hpp; fixed many, many VS2005, VS2010 and MinGW (GCC 4.5.2) warnings

a big patch; use special proxy types (Input/OutputArray, Input/OutputArrayOfArrays) for passing in vectors, matrices etc.

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