First pass at C# conformance tests.

Completely untested so far - easier to get started in VS and then transfer to Linux for tweaking...
diff --git a/csharp/generate_protos.sh b/csharp/generate_protos.sh
index 2b5e525..962f2a9 100755
--- a/csharp/generate_protos.sh
+++ b/csharp/generate_protos.sh
@@ -68,3 +68,6 @@
 # AddressBook sample protos
 $PROTOC -Iexamples --csharp_out=csharp/src/AddressBook \
     examples/addressbook.proto
+
+$PROTOC -Iconformance --csharp_out=csharp/src/Google.Protobuf.Conformance \
+    conformance/conformance.proto