Extend C# complex support to member variables of this type

Define csvar{in,out} typemaps needed to support properties of complex type and
apply the existing cstype and csin ones to them as well.

Add unit test verifying that this works as expected in C# and, also, in
Python, even though no changes were needed there.

Examples/test-suite/python/complextest_runme.py

@@ -15,3 +15,9 @@ try:
     complextest.Copy_h(v)
 except:
     pass
+
+p = complextest.ComplexPair()
+p.z1 = complex(0, 1)
+p.z2 = complex(0, -1)
+if complextest.Conj(p.z2) != p.z1:
+    raise RuntimeError, "bad complex mapping"