Log Message:
update to gerbv-0.16.

additions/changes since gerbv-0.15:

* projects: you can save and load setups in what I call projects.
* GTK+ 2 support
* Now you can invert a layer by the push of button. Basically.
* When gerber files were defined with omit trailing zeros, gerbv could
  parse them very bad. Now it should work better.
* Aperture macros did not handle exposures at all. Now they do a better
  work.  Some thermals are defined from their CAD program as a sequence of
  aperture macros instead of just using aperture macro 7. They are drawn
  better now.
* Handles tool tables when drawing drill files thanks to Dimitri. See man
  page for more info.