Update cut_to_disk.cpp

move headers to cpp

Former-commit-id: bfa6e9a716c678b5b598c565b46752b46a1c8ab1

include/igl/cut_to_disk.cpp

@@ -1,5 +1,10 @@
 #include <igl/cut_to_disk.h>
 
+#include <map>
+#include <set>
+#include <deque>
+#include <algorithm>
+
 namespace igl {
   template <typename DerivedF, typename Index>
   void cut_to_disk(