Made separate functions for computing output shapes for all layers. Removed output blobs allocation from layers

The other implementation of reconstruct() had the flag enabled. Enabling
it here as well for consistency

change braces in abs() call
resolves: #1157

fixed typo

replaces Mat& to Input/OutputArray in public methods.

small fix.

small fixes

* Fixed bugs after dnn refactoring. Added new tests for layers

* Fixed torch tests

* the first commit in the merged dnn: convert some public API from Blob's to Mat's

* temporarily or permantently removed OpenCL optimizations, which are not always stable nor usually very efficient; we'll likely use Halide instead

* got rid of Blob and BlobShape completely; use cv::Mat and std::vector<int> instead

* fixed a few compile errors

* got rid of separate .hpp files with layer declarations; instead, put everything into the respective .cpp files

* normalized all the layers' constructors; we concentrate on loading deep networks layers from files instead of constructing them from scratch, so we retained only SomeLayer::SomeLayer(const LayerParams& params); constructors

* fixed sample compilation

* suppress doxygen warnings

* trying to fix python bindings generation for DNN module

* temporarily disable python bindings while we refactor the module

* fix win32/win64 compile errors; remove trailing whitespaces

* fix win32/win64 compile errors; remove trailing whitespaces

Correcting bgsegm module descriptions.  (#493)

* Correcting bgsegm module descriptions. The algorithm implementation doesn't have multi target tracking as mentioned in original paper. it only does foreground/background segmentation.

* Removing opencv_ from heading

Removing opencv_ from description

fixing matlab wrapping