add missing bit definition for NG-RAN in xAcT

when encoding the AcT value bit 11 is correctly set
when NG-RAN is present in the string representation,
however the decoding of bit 11 was missing.
Adds tests for the decoder as well.

Change-Id: I910df28c4c59ec94cce9603377786325f6d8c1a3
diff --git a/pysim-testdata/Fairwaves-SIM.ok b/pysim-testdata/Fairwaves-SIM.ok
index 2a912e2..f07c033 100644
--- a/pysim-testdata/Fairwaves-SIM.ok
+++ b/pysim-testdata/Fairwaves-SIM.ok
@@ -31,7 +31,7 @@
 	ffffff0000 # unused
 
 HPLMNAcT:
-	00f110ffff # MCC: 001 MNC: 01 AcT: UTRAN, E-UTRAN WB-S1, E-UTRAN NB-S1, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
+	00f110ffff # MCC: 001 MNC: 01 AcT: UTRAN, E-UTRAN WB-S1, E-UTRAN NB-S1, NG-RAN, GSM, GSM COMPACT, cdma2000 HRPD, cdma2000 1xRTT
 	ffffff0000 # unused
 	ffffff0000 # unused
 	ffffff0000 # unused