Fix path errors with multi-tuple M,m conversion.

I've been using svglib in a Electrum plugin for paper wallet printing with svg templates. The original svg file I have as source was generated using Adobe Illustrator (and Inkscape) and contains many m x,y x,y x,y type sequences. But svglib does not currently render these correctly. These are text chars converted to paths and many letters get dropped when I render using svglib.

I've tracked down and fixed this and tested it with my svg files. It now works correctly for me, and I believe will work generally with arbitrary M/m repeat sequences.