fix accessing empty vector data
use C++ enums instead of old #define macros in the C interface
update function docs
add usage example

code adapted from OpenCV documentation page
update docs of putText
Merge pull request #79 from amroamroamro/gettextsize_bug

Fixed cv.getTextSize
small fix on pointPolygonTest

wrapping cells and numeric matrixes as the others
Makefile update; Style update