Add std::unique support

Simple copy of current auto_ptr support (just suppport for
functions returning std::unique_ptr).

Closes #1722

Examples/test-suite/python/cpp11_std_unique_ptr_runme.py

@@ -0,0 +1,17 @@
+from cpp11_std_unique_ptr import *
+
+k1 = makeKlassUniquePtr("first")
+k2 = makeKlassUniquePtr("second")
+if Klass.getTotal_count() != 2:
+    raise "number of objects should be 2"
+
+del k1
+if Klass.getTotal_count() != 1:
+    raise "number of objects should be 1"
+
+if k2.getLabel() != "second":
+    raise "wrong object label"
+
+del k2
+if Klass.getTotal_count() != 0:
+    raise "no objects should be left"