Remove some hacks related to postprocessing (not need now because the
previous postprocessing improvements, light parametrization could be
used for tune or future parameters could be implemented)
This introduces layer handling to a lot of the geometry routines.
Many of them don't do much with it now, but it does help multi-layer
zones and will help when padstacks are implemented.
There were a lot of plotters, exporters, etc. that were rolling their
own implementations.
This also introduces a lazily-built set of SHAPE objects for doing
collision detection and some forms of rendering (and later DRC).
Move the camera out to its own so that everything else is board-
related, and then rename BOARD_ADAPTER.
At some point the flags should probably be moved out too, and they
can have the EDA_3D_SETTINGS name.
