Add Missing Includes Across src/libslic3r

Every libslic3r source and header now directly includes the headers declaring what it uses, rather than relying on the precompiled header or transitive includes. Generated with clang-tidy misc-include-cleaner, with libslic3r headers spelled libslic3r/... so they resolve outside the library's private include paths. MultiMaterialSegmentation.hpp, Support/SupportParameters.hpp and Format/STEP.hpp are made self-contained by hand.

src/libslic3r/PrintObjectSlice.cpp

@@ -1,16 +1,42 @@
+#include <algorithm>
 #include <boost/log/trivial.hpp>
 
+#include <cstddef>
+#include <functional>
+#include <cassert>
+#include <cstdlib>
+#include <memory>
+#include <math.h>
+#include <cmath>
+#include <iterator>
 #include <tbb/parallel_for.h>
+#include <vector>
+#include <utility>
 
+#include "BoundingBox.hpp"
 #include "ClipperUtils.hpp"
 #include "ElephantFootCompensation.hpp"
+#include "ExPolygon.hpp"
 #include "Exception.hpp"
+#include "Flow.hpp"
 #include "I18N.hpp"
 #include "Layer.hpp"
+#include "Model.hpp"
 #include "MultiMaterialSegmentation.hpp"
+#include "ObjectID.hpp"
+#include "Point.hpp"
+#include "Polygon.hpp"
 #include "Print.hpp"
 //BBS
+#include "PrintConfig.hpp"
+#include "PrintBase.hpp"
 #include "ShortestPath.hpp"
+#include "libslic3r.h"
+#include "TriangleMeshSlicer.hpp"
+#include "TriangleMesh.hpp"
+#include "Slicing.hpp"
+#include "Surface.hpp"
+#include "Utils.hpp"
 #include "libslic3r/Feature/Interlocking/InterlockingGenerator.hpp"
 
 //! macro used to mark string used at localization, return same string