Added St extension and modified Rx Gx to avoid conflict

Change-Id: Ie3a09088eae83e1dff82ff82051e6345c103c171
diff --git a/extensions/dict_St/St.did b/extensions/dict_St/St.did
new file mode 100644
index 0000000..2cb334c
--- /dev/null
+++ b/extensions/dict_St/St.did
@@ -0,0 +1,38 @@
+dict_rfc6942_avps
+dict_ts29468_avps
+dict_ts29154_avps
+dict_ts29214_avps
+dict_ts29215_avps
+dict_ts29217_avps
+dict_3gpp2_avps
+dict_ts29343_avps
+dict_ts29338_avps
+dict_ts29128_avps
+dict_ts29344_avps
+dict_ts29345_avps
+dict_ts32299_avps
+dict_rfc6734_avps
+dict_rfc5778_avps
+dict_rfc5580_avps
+dict_rfc4072_avps
+dict_ts29273_avps
+dict_ts29173_avps
+dict_ts29337_avps
+dict_etsi283034_avps
+dict_rfc4590_avps
+dict_ts29229_avps
+dict_draftload_avps
+dict_ts29329_avps
+dict_ts29368_avps
+dict_ts29336_avps
+dict_ts29061_avps
+dict_rfc5447_avps
+dict_ts29272_avps
+dict_rfc7683_avps
+dict_ts29212_avps
+dict_rfc5777_avps
+dict_rfc4006bis_avps
+dict_rfc4004_avps
+dict_rfc7155_avps
+dict_rfc7944_avps
+dict_St