[clib] Fix bounds check on getMolecularWeights

The incorrect bounds check here caused problems with phases where
there were more elements than species.

Fixes Issue 173.

src/clib/ct.cpp

@@ -280,7 +280,7 @@ extern "C" {
     {
         try {
             ThermoPhase& p = ThermoCabinet::item(n);
-            p.checkElementArraySize(lenm);
+            p.checkSpeciesArraySize(lenm);
             const vector_fp& wt = p.molecularWeights();
             copy(wt.begin(), wt.end(), mw);
             return 0;