src: port openBSC over libosmo-abis

This is a big patch that ports openBSC over libosmo-abis.
Sorry, the changes that are included here are all dependent
of libosmo-abis, splitting them into smaller pieces would
leave the repository in some intermediate state, which is
not desired.

The main changes are:

- The directory libabis/ has been removed as it now lives in
  libosmo-abis.

- new configuration file format for nanoBTS and HSL femto, we
  need to define the virtual e1_line and attach it to the OML
  link.

- all the existing BTS drivers (nanoBTS, hsl femto, Nokia site,
  BS11 and rbs2000) now use the new libosmo-abis framework.

- use r232 input driver available in libosmo-abis for bs11_config.

- use ipa_msg_recv instead of old ipaccess_read_msg function.

- delete definition of gsm_e1_subslot and input_signal_data.
  These structures now lives in libosmo-abis.

Most of this patch are deletions of libabis/ which has been
moved to libosmo-abis.

This patch also modifies openBSC to use all the new definitions
available in libosmocore and libosmo-abis. In order to do that,
we have replaced the following:

- DINP, DMI, DMIB and DMUX by their respective DL* correspondences.
- SS_GLOBAL by SS_L_GLOBAL
- SS_INPUT by SS_L_INPUT
- S_GLOBAL_SHUTDOWN by S_L_GLOBAL_SHUTDOWN
- SS_INPUT by SS_L_INPUT
- S_INP_* by S_L_INP_* sub-signals
- E1INP_NODE by L_E1INP_NODE vty node

This patch has been tested with:
- one nanoBTS
- the HSL femto with the examples available under libosmo-abis
- BS11 with both dahdi and misdn drivers.
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index 89375cf..1dec0e4 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -225,16 +225,6 @@
 #endif
 };
 
-
-struct gsm_e1_subslot {
-	/* Number of E1 link */
-	uint8_t	e1_nr;
-	/* Number of E1 TS inside E1 link */
-	uint8_t	e1_ts;
-	/* Sub-slot within the E1 TS, 0xff if full TS */
-	uint8_t	e1_ts_ss;
-};
-
 #define TS_F_PDCH_MODE	0x1000
 /* One Timeslot in a TRX */
 struct gsm_bts_trx_ts {
@@ -341,6 +331,8 @@
 	int (*start)(struct gsm_network *net);
 	int (*oml_rcvmsg)(struct msgb *msg);
 
+	void (*e1line_bind_ops)(struct e1inp_line *line);
+
 	void (*config_write_bts)(struct vty *vty, struct gsm_bts *bts);
 	void (*config_write_trx)(struct vty *vty, struct gsm_bts_trx *trx);
 	void (*config_write_ts)(struct vty *vty, struct gsm_bts_trx_ts *ts);