Add function for appending range1024 to bitvec

Add convenience function to append range1024 encoded data (see 3GPP TS
44.018 Annex J) to a given bitvec.
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index a526756..f9a8369 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -25,7 +25,7 @@
 abis_nm_ipa_magic;
 
 osmo_sitype_strs;
-
+bitvec_add_range1024;
 comp128;
 dbm2rxlev;