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.