Introduce new file for various measurements

The measurements include:
- DL bandwidth usage
- DL packet loss rate
- DL measurements by mobile
- UL measurements by BTS

In order to receive DL measurements from mobile, it must be enabled via
system information message at BSC.
diff --git a/src/gprs_debug.h b/src/gprs_debug.h
index abd5d95..8b113a1 100644
--- a/src/gprs_debug.h
+++ b/src/gprs_debug.h
@@ -38,7 +38,7 @@
 	DRLCMACDL,
 	DRLCMACUL,
 	DRLCMACSCHED,
-	DRLCMACBW,
+	DRLCMACMEAS,
 	DBSSGP,
 	DPCU,
 	aDebug_LastEntry