Add command line option to plot (lp:#1448518)

Original report created by Thomas Wirsing (twirsing)

I would like to create plots and SVG-exports from the command line.
This would reduce the risk of making mistakes when reproducing a printed
circuit boards.

Here an example of this features at eagle:
eagle -X -dPS -otop_p.ps meineplatine.brd Dimension tPlace tNames tValues
Vias Unrouted
eagle -X -dPS -obot_p.ps meineplatine.brd Dimension bPlace bNames bValues
-m
eagle -X -dPS -otop_k.ps meineplatine.brd Top    Pads Vias -f- -m
eagle -X -dPS -obot_k.ps meineplatine.brd Bottom Pads Vias -f-
eagle -X -dPS -osch.ps   meineplatine.sch -s0.55
eagle -X -dPS -oall.ps   meineplatine.brd -f-

Original tags: eeschema pcbnew python