Removed GCode.pm
Removed the Perl bindigns for AvoidCrossingPerimeters, OozePrevention, SpiralVase, Wipe
Changed the std::set of extruder IDs to vector of IDs.
Removed some MSVC compiler warnings, removed obnoxious compiler warnings when compiling the Perl bindings.
Removed the questionable Pressure Advance feature. It is better to use the Pressure Advance implemented into a firmware.
Added a C++ implementation of GCodeReader and SpiralVase, thanks to @alexrj
Added a C++ implementation of GCodeTimeEstimator, thanks to @lordofhyphens
