Cycles: Re-implement some utilities to avoid use of boost

The title says it all actually, the idea is to make Cycles
only requiring Boost via 3rd party dependencies like OIIO
and OSL.

So now there are only few places which still uses Boost:

- Foreach, function bindings and threading primitives.

  Those we can easily get rid with C++11 bump (which seems
  inevitable sooner or later if we'll want ot use newer
  LLVM for OSL),

- Networking devices

  There's no quick solution for those currently, but there
  are some patches around which improves serialization.

Reviewers: juicyfruit, mont29, campbellbarton, brecht, dingto

Reviewed By: brecht, dingto

Differential Revision: https://developer.blender.org/D1764

intern/cycles/util/util_system.cpp

@@ -20,15 +20,15 @@
 #include "util_string.h"
 
 #ifdef _WIN32
-#if(!defined(FREE_WINDOWS))
-#include <intrin.h>
-#endif
-#include <windows.h>
+#  if(!defined(FREE_WINDOWS))
+#    include <intrin.h>
+#  endif
+#  include "util_windows.h"
 #elif defined(__APPLE__)
-#include <sys/sysctl.h>
-#include <sys/types.h>
+#  include <sys/sysctl.h>
+#  include <sys/types.h>
 #else
-#include <unistd.h>
+#  include <unistd.h>
 #endif
 
 CCL_NAMESPACE_BEGIN