Added UNUSED macro to libslic3r.h, used it to reduce some compile warnings.
Split the Int128 class from Clipper library to a separate file,
extended Int128 with intrinsic types wherever possible for performance,
added new geometric predicates.
Added a draft of new FillRectilinear3, which should reduce overfill near the perimeters in the future.
Removed dependency on Perl Math::PlanePath module.
Fixed compilation with Visual Studio and SLIC3R_DEBUG: Visual Studio older than 2015 does not support the prinf type specifier %zu. Use %Iu instead.
C++11 move semantics enabled.