[Feature request] add pattern support

[jorgerobles]

Implementing pattern support for complex drawings.

[jorgerobles]

I'm trying to add support to pattern using a simple approach, adding patterns dictionary as symbol/defs, and then append pattern contents as tag children. This would be repeated until fill bounds and then applying clipper boolean operation.

Currently stuck at https://github.com/jorgerobles/lw.svg-parser/tree/pattern_support 😄