- 'clear' polarity primitives no longer erase background
- Added aperture macro support for polygons
- Added aperture macro rendring support
- Renderer now creates a new surface for each layer and merges them instead of working
directly on a single surface
- Updated examples accordingly
this incorporates some of @chintal's layers.py changes
PCB.from_directory() simplifies loading of multiple gerbers
the PCB() class should be pretty helpful going forward...
the context classes could use some cleaning up, although I'd like to wait until the freecad stuff gets merged, that way we can try to refactor the context base to support more use cases
FS D leading zero format (probably form Direct) is an unspecified
coordinate format where all numbers are specified with both leading
and trailing zeros.
If we parse a file with 5.5 INCH format and ask to write
it back as 2.4 INCH we are going to loose precision and
write_gerber_value was not handling these cases write.
