add BSSLAP coding for Location Services

BSSLAP: there are APDUs transferred in BSSMAP-LE Connection Oriented
Information messages on Lb between BSC and SMLC.
Add BSSLAP coding for these APDU messages:
- TA Layer3
- TA Request
- TA Response, possibly containing Location Estimate coded in GAD
- Reject
- Reset (for intra-BSS handover during TA Request)
- Abort (for inter-BSS handover)

Add encoding and decoding tests.

Change-Id: I6409c4bcac402dc7626a3afce9081c59cd715fe8
diff --git a/tests/testsuite.at b/tests/testsuite.at
index e29c131..0923c25 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -409,3 +409,9 @@
 cat $abs_srcdir/gad/gad_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/gad/gad_test], [0], [expout], [ignore])
 AT_CLEANUP
+
+AT_SETUP([bsslap])
+AT_KEYWORDS([bsslap])
+cat $abs_srcdir/bsslap/bsslap_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/bsslap/bsslap_test], [0], [expout], [ignore])
+AT_CLEANUP