Fixed minor compile errors:

- Lack of <functional> in AStarPathfinder.h
 - Lack of <cstdint> in several files (why did this compile on GCC?)

library/PolyVoxCore/include/PolyVoxCore/AStarPathfinder.h

@@ -29,14 +29,10 @@ freely, subject to the following restrictions:
 
 #include "PolyVoxCore/Array.h"
 
+#include <functional>
 #include <list>
 #include <stdexcept> //For runtime_error
 
-namespace std {
-template<class _Signature >
-class function;
-}
-
 namespace PolyVox
 {
 	const float sqrt_1 = 1.0f;

library/PolyVoxCore/include/PolyVoxCore/DefaultIsQuadNeeded.h

@@ -26,6 +26,8 @@ freely, subject to the following restrictions:
 
 #include "PolyVoxCore/Impl/TypeDef.h"
 
+#include <cstdint>
+
 namespace PolyVox
 {
 	template<typename VoxelType>

library/PolyVoxCore/include/PolyVoxCore/Impl/SubArray.h

@@ -26,6 +26,8 @@ freely, subject to the following restrictions:
 
 #include "PolyVoxCore/Impl/TypeDef.h"
 
+#include <cstdint>
+
 namespace PolyVox
 {
 	template <uint32_t noOfDims, typename ElementType> class Array;

library/PolyVoxCore/include/PolyVoxCore/Impl/Utility.h

@@ -26,6 +26,8 @@ freely, subject to the following restrictions:
 
 #include "PolyVoxCore/Impl/TypeDef.h"
 
+#include <cstdint>
+
 namespace PolyVox
 {
 	POLYVOX_API uint8_t logBase2(uint32_t uInput);