Fix invocation of PythonType2LSL

Fixes #32. Thanks to @KrsityKu for the report and repro.

unit_tests/regression.suite/issue-32.lsl

@@ -0,0 +1,8 @@
+default
+{
+    timer()
+    {
+        vector v = <1,2,3>;
+        llOwnerSay((string)v.x);
+    }
+}

unit_tests/regression.suite/issue-32.out

@@ -0,0 +1,7 @@
+default
+{
+    timer()
+    {
+        llOwnerSay("1.000000");
+    }
+}