CallableTracer: fix namespace and decouple from SMO::OptionsParser

We now have a static local var that informs libspinscale whether or
not to print the callable traces at runtime.

src/callableTracer.cpp

@@ -0,0 +1,7 @@
+#include <spinscale/callableTracer.h>
+
+namespace sscl {
+
+bool CallableTracer::optTraceCallables = false;
+
+} // namespace sscl