added getBool() to Slic3r::Config interface.
added getBool() to Slic3r::Config interface.

lordofhyphens/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,alexrj/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,lordofhyphens/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,curieos/Slic3r,lordofhyphens/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,lordofhyphens/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,curieos/Slic3r,curieos/Slic3r