* removed private flann documentation
* common tutorial images moved to doc/images
* grouping issues

Add overloaded cv::PCACompute() that returns also the eigenvalues. Useful for Java and Python OpenCV where PCA is not available.

If this seems too wordy, take into account a new user who tries to find out extent of FP16 support in OpenCV.

Still need to remove the descriptions of these flags from cv::norm

Added forkfour Latex command to math js support.

Split cv::norm documentation between the cv::norm and its overload, to make things clearer

Corrected some typos and cleaned up grammar.

Result is clearer documentation for the norms.

Work pending...

This adds the possibility to use multi-channel masks for the functions
cv::mean, cv::meanStdDev and the method Mat::setTo. The tests have now a
probability to use multi-channel masks for operations that support them.
This also includes Mat::copyTo, which supported multi-channel masks
before, but there was no test confirming this.

Add demo code for cv::reduce, cv::merge and cv::split.

SoftFloat: added sin, cos and docs (#9329)

* softfloat: comparison operators made inline, min() max() eps() isSubnormal() added

* softfloat: get/set sign/exp

* softfloat: get/set frac

* softfloat: tests rewritten with new tools

* softfloat: added pi(), sin(), cos()

* softfloat: more comments

* softfloat: updated sincos arg reduction

* softfloat: initial tests for sincos added

* softfloat: test works, code cleanup is pending

* softfloat: sincos argreduce rewritten

* softfloat: sincos refactored and simplified

* softfloat sincos: epsilons calibrated

* softfloat: junk code removed from tests

* softfloat: docs added

* inline comparisons undone; warning fixed

NORM_RELATIVE | NORM_INF, NORM_RELATIVE | NORM_L1 and NORM_RELATIVE | NORM_L2
respectively in the documentation for cv::norm and cv::NormTypes

* everything is put into softfloat.cpp and softfloat.hpp

* WIP: try to integrate softfloat into OpenCV

* extra functions removed

* softfloat made stateless

* CV_EXPORTS added

* operators fixed

* exp added, log: WIP

* log32 fixed

* shorter names; a lot of TODOs

* log64 rewritten

* cbrt32 added

* minors, refactoring

* "inline" -> "CV_INLINE"

* cast to bool warnings fixed

* several warnings fixed

* fixed warning about unsigned unary minus

* fixed warnings on type cast

* inline -> CV_INLINE

* special cases processing added (NaNs, Infs, etc.)

* constants for NaN and Inf added

* more macros and helper functions added

* added (or fixed) tests for pow32, pow64, cbrt32

* exp-like functions fixed

* minor changes

* fixed random number generation for tests

* tests for exp32 and exp64: values are compared to SoftFloat-based naive implementation

* minor warning fix

* pow(f, i) 32/64: special cases handling added

* unused functions removed

* refactoring is in progress (not compiling)

* CV_inline added

* unions {uint_t, float_t} removed

* tests compilation fixed

* static const members -> static methods returning const

* reinterpret_cast

* warning fixed

* const-ness fixed

* all FP calculations (even compile-time) are done in SoftFloat + minor fixes

* pow(f, i) removed from interface (can cause incorrect cast) to internals of pow(f, f), tests fixed

* CV_INLINE -> inline

* internal constants moved to .cpp file

* toInt_minMag() methods merged into toInt() methods

* macros moved to .cpp file

* refactoring: types renamed to softfloat and softdouble; explicit constructors, etc.

* toFloat(), toDouble() -> operator float(), operator double()

* removed f32/f64 prefixes from functions names

* toType() methods removed, round() and trunc() functions added

* minor change

* minors

* MSVC: warnings fixed

* added int cvRound(), cvFloor, cvCeil, cvTrunc, saturate_cast<T>()

* typo fixed

* type cast fixed