renamed RepRapBuilder to RepRapPlater and ...

removed IOException from produce() method signature
trying to get rid of global Configuration.getInstance()

Goal: explicit creation in MainFrame and passed down to the consumers.
Cant do this immediately, but need to clean up Attributes first (depends
on 3d and configuration used as UserData in branch groups).

This change:
* create configuration in MainFrame
* pass down to PrintTabFrame, RepRapPlater
also
* removed superfluous null checks and unused parameters
* moved field initialization into constructor of RFO
tests spot the missing initialization of the configuration :-)
reduce usage of Attributes in SimulationPlotter
get rid of Attributes in Polygon
replaced Attributes in BooleanGrid with material
reduced logging level to INFO
removed Attribute from LineSegment and split ...

from addSTL a method specific for adding an independent stl file
decoupled material and appearance in Attributes

* only setting the appearance triggers a restoreAppearance in the parent
* moved knowledge about the relation between materials and appearances
  to the STLObject
* RfoXMLHandler simplified
moved LineSegment to the other polygons
progress with explicit creation of configuration

pushed down to:
* Producer, GCodePrinter, GCodeWriter, GCodeExtruder
* RepRapPlater, STLObject, RFO, RfoXmlHandler, MaterialRadioButtons

also: 
* simplified exception handling
* refactored saveRfo in MainFrame
* moved checkFile from RFO to RepRapPlater
* simplified File handling in RFO