Fix overloaded templates and default arguments

The defaultargs attribute was not being correctly set for functions with
default arguments when instantiated with %template.

Closes #529

Examples/test-suite/template_default_arg_overloaded.i

@@ -0,0 +1,67 @@
+%module template_default_arg_overloaded
+
+// Github issue #529
+
+%include <std_string.i>
+
+%inline %{
+#include <string>
+
+namespace lsst {
+namespace daf {
+namespace bass {
+
+class PropertyList {
+public:
+    PropertyList(void) {};
+
+    virtual ~PropertyList(void) {};
+
+    template <typename T> int set(std::string const& name1, T const& value1, bool inPlace1=true) { return 1; }
+
+    int set(std::string const& name2, PropertyList const& value2, bool inPlace2=true) { return 2; }
+
+    template <typename T> int set(std::string const& name3, T const& value3, std::string const& comment3, bool inPlace3=true) { return 3; }
+};
+
+}}} // namespace lsst::daf::bass
+
+// As above but in global namespace
+class PropertyListGlobal {
+public:
+    PropertyListGlobal(void) {};
+
+    virtual ~PropertyListGlobal(void) {};
+
+    template <typename T> int set(std::string const& name1, T const& value1, bool inPlace1=true) { return 1; }
+
+    int set(std::string const& name2, PropertyListGlobal const& value2, bool inPlace2=true) { return 2; }
+
+    template <typename T> int set(std::string const& name3, T const& value3, std::string const& comment3, bool inPlace3=true) { return 3; }
+};
+
+%}
+
+%template(setInt) lsst::daf::bass::PropertyList::set<int>;
+%template(setIntGlobal) PropertyListGlobal::set<int>;
+
+
+// Global functions
+%inline %{
+template<typename T> int goopGlobal(T i1, bool b1 = true) { return 1; }
+int goopGlobal(short s2 = 0) { return 2; }
+template<typename T> int goopGlobal(const char *s3, bool b3 = true) { return 3; }
+%}
+
+// Global functions in a namespace
+%inline %{
+namespace lsst {
+template<typename T> int goop(T i1, bool b1 = true) { return 1; }
+int goop(short s2 = 0) { return 2; }
+template<typename T> int goop(const char *s3, bool b3 = true) { return 3; }
+}
+%}
+
+%template(GoopIntGlobal) goopGlobal<int>;
+%template(GoopInt) lsst::goop<int>;
+