fixing bug #3345
Improved documentation for neural network
Added throwing exception when saving untrained SVM model
fixing bug #3345. don't use BORDER_ISOLATED alone. it should be combined with some border type
Fixed cvtColor alpha channel docs
Merge pull request #2143 from Daniil-Osokin:fix_docs_cvt_color_alpha_channel
Revert "fixed bug #3319"

See 092f916 for explanation.

This reverts commit 4f9c081dc313f8fdfee3f0a4572779ae13e27e40.
Re-fix bug #3319 with less side effects.
Removed an unnecessary workaround for matrix-to-vector copyTo.
Added a test for matrix-to-vector copy and convert.
Merge pull request #2140 from Daniil-Osokin:fix_saving_untrained_svm_model
Merge pull request #2159 from SpecLad:1xN
Fixed bug #3489: The code assumed that two global variables would be constructed in a particular order, but global variable initialization order is compiler-dependent.
Merge pull request #2171 from djetter99:fix_static_init_order
fix cross-compilation issue with Numpy
reorder the if's for clarity
split CUDA Hough sources
disable CUDA generalized Hough Transform
Merge pull request #2107 from nghiaho12:nn_doc
Merge pull request #2183 from jet47:cuda-hough-fix