Move SDP templates to its own SDP_Templates.ttcn file

SDP is used in other protocols than MGCP, eg. SIP.

Change-Id: I0610b4cf5533e46a3401c65e60c7cce975c85412
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index 7f993c4..9db18d3 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -46,6 +46,7 @@
 import from MGCP_Types all;
 import from MGCP_Templates all;
 import from SDP_Types all;
+import from SDP_Templates all;
 
 import from GSUP_Types all;
 import from GSUP_Templates all;