Add a GSM RLP decoder and encoder

This code implements a decoder and encoder for the RLP (Radio Link
Protocol) as used in the bearer channel of GSM CSD (Circuit Switched
Data).

Change-Id: I2d9bd8eb4f0cd0f72c436996767b199429596917
diff --git a/tests/testsuite.at b/tests/testsuite.at
index aacdad7..64ebedf 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -519,3 +519,9 @@
 cat $abs_srcdir/soft_uart/soft_uart_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/soft_uart/soft_uart_test], [0], [expout], [ignore])
 AT_CLEANUP
+
+AT_SETUP([rlp])
+AT_KEYWORDS([rlp])
+cat $abs_srcdir/rlp/rlp_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/rlp/rlp_test], [0], [expout], [ignore])
+AT_CLEANUP