NanoSVG port

[ketmar via Digitalmars-d-announce]

i also made NanoSVG[1] port[2]: simple SVG parser and rasterizer. 
it is using `malloc()` to allocate memory, but otherwise was 
rewritten to use `const(char)[]` input for svg, and do not use 
`sscanf()` from libc.

the port lives in NanoVG package, but it is actually completely 
independent.


[1] https://github.com/memononen/nanosvg
[2] http://repo.or.cz/iv.d.git/blob_plain/HEAD:/nanovg/svg.d