Reduced the content of Geometry.pm, removed unused Perl subroutines.

Reduced the use Slic3r::Geometry and use Slic3r::Geometry::Clipper
clauses to only reference used subroutines.

lib/Slic3r/ExPolygon.pm

@@ -5,7 +5,6 @@ use warnings;
 # an ExPolygon is a polygon with holes
 
 use List::Util qw(first);
-use Slic3r::Geometry qw(X Y A B point_in_polygon epsilon scaled_epsilon);
 use Slic3r::Geometry::Clipper qw(union_ex diff_pl);
 
 sub wkt {
@@ -43,7 +42,6 @@ sub bounding_box {
 }
 
 package Slic3r::ExPolygon::Collection;
-use Slic3r::Geometry qw(X1 Y1);
 
 sub size {
     my $self = shift;