Incorrect path parsing with multiple-valued h and v commands.

[mwebb759]

When multiple values are given for an 'h' or 'v' command, only the first is used, all others are ignored.

The following openscad script

include <./include/pathbuilder/pathbuilder.scad>
path = svgPoints("m 0,0 l 10,10 h -5 -5 z");
echo(path);
polygon(path[0]);

produces this preview:

and emits:

ECHO: [[[0, 0], [10, 10], [5, 10], [0, 0]]]

whereas, the same path in inkscape shows as:

Inkscape will also produce paths written in this way.

I haven't checked if this is an issue for commands other than 'h' and 'v'.