[beta] moar conditional gcode edition

new

• a new conditional gcode window, that trigger on every extrusion role change (external_perimeter -> internal_perimeter -> infill -> gapfill). #108
• a setting to add a perimeter every odd layer, to make a sandwich with infill, to be able to set the perimeter/infill overlap setting very low, to maybe CORRECT THAT more easily. #89
• add an other parameter for ironing : you are now able to choose the amount of plastic that will be used for the second pass (typical 10%) #101

bugfix

• fix linux build
• change the version numbering to allow prusa .ini #105
• don't allow infill to set "always bridge" #110
• optimized function #106
• revert a very bad idea #103