xrCore.h: Fixed rt_compressor include.

Author: Kaffeine

src/xrCore/xrCore.h

@@ -122,7 +122,7 @@
 #include "xrsharedmem.h"
 #include "xrstring.h"
 #include "xr_resource.h"
-#include "Compression\rt_compressor.h"
+#include "Compression/rt_compressor.h"
 #include "xr_shared.h"
 #include "string_concatenations.h"