Add VerticalDrawText to Python bindings

[mcsarge]

There is a routine that is not available in the Python binding. I have tried to add it, but my knowledge of c++ and cython is not strong enough to make the change. The trouble appears to be that in the cpp for VerticalDrawText, the background color is passed as "*" unlike color, which is passed as a "&". I do not know how to change the includes and .cpp code to account for this and to pass such a value and I can find no similar example.