Matrix constructor from rows, cols, Buffer, step

[piercus]

Adding the constructor signature like https://docs.opencv.org/2.4/modules/core/doc/basic_structures.html#Mat::Mat(int%20rows,%20int%20cols,%20int%20type,%20void*%20data,%20size_t%20step)

[UrielCh]

For this kind of change, I think that you should add a test in tests/core/Mat/constructorTestsFromFillVector.ts or tests/core/Mat/constructorTestsFromJsArray.ts

Please do it before I enforce "noImplicitAny": true in the tests (currently Found 553 errors.).

[piercus]

@UrielCh please review

[UrielCh]

leave it to appveyor :)