Add testcase for nested inner class deriving from a templated base class and defined outside of the outer class.

For languages that don't support nested class support, use flatnested.
See issue #270

Examples/test-suite/nested_template_base.i

@@ -0,0 +1,38 @@
+%module nested_template_base
+
+%inline %{
+  template <class T> class OuterT {
+    public:
+      T outer(T t) { return t; }
+  };
+%}
+ 
+// The %template goes after OuterT and before OuterC as OuterC::InnerC's base is handled inside OuterC
+%template(OuterTInnerS) OuterT<OuterC::InnerS>;
+
+#if !defined(SWIGCSHARP) && !defined(SWIGJAVA)
+%feature("flatnested") OuterC::InnerS;
+%feature("flatnested") OuterC::InnerC;
+#endif
+
+
+%inline %{
+  class OuterC {
+  public:
+    class InnerS;
+    class InnerC;
+  };
+ 
+  struct OuterC::InnerS {
+    int val;
+    InnerS(int val = 0) : val(val) {}
+  };
+
+
+  class OuterC::InnerC : public OuterT<InnerS> {
+  public:
+    OuterT<InnerS>& innerc() {
+      return *this;
+    }
+  }; 
+%}