Refactor C++ code

Split features into their own file

Style is becoming less C, more C++

src/utilities.h

@@ -0,0 +1,10 @@
+#ifndef SHARP_UTILITIES_H
+#define SHARP_UTILITIES_H
+
+#include "nan.h"
+
+NAN_METHOD(cache);
+NAN_METHOD(concurrency);
+NAN_METHOD(counters);
+
+#endif