This way one knows if he is using the old or STM library by looking at
the include line, while the sketch should compile file as the functions
are named the same. I believe this is the best compromise.
Added DMA support for STM32F1xx, and extra check in line and rect
funtions to avoid trying to draw a 0 width or 0 height line/rectangle,
which would cause 0 bytes DMA transmission and hang in a loop.
victorpv