pySim-read.py: fix reading and parsing of EF.MSISDN

This change implements parsing of EF.MSISDN (and thus EF.ADN)
as per 3GPP TS 31.102, sections 4.2.26 and 4.4.2.3.

Example (commercial SIM card from 401/02):

  EF.MSISDN: ffffffffffffffffffffffffffff07917787028982f7ffffffffffff
  Decoded (NPI=1 ToN=1): +77782098287

Note that sysmoUSIM-SJS1 in the test setup has malformed
EF.MSISDN, so that's why the test output is changed.

Change-Id: Ie914ae83d787e3f1a90f9f305bffd45053b8c863

pysim-testdata/sysmoISIM-SJA2.ok

@@ -50,7 +50,7 @@ HPLMNAcT:
 	ffffff0000 # unused
 
 ACC: 0001
-MSISDN: Not available
+MSISDN (NPI=1 ToN=1): +1234
 AD: 00000002
 Done !
 

pysim-testdata/sysmoUSIM-SJS1.ok

@@ -50,7 +50,7 @@ HPLMNAcT:
 	ffffff0000 # unused
 
 ACC: 0008
-MSISDN: Not available
+MSISDN: Can't read file -- Length of MSISDN (136 bytes) is out of range
 AD: 00000002
 Done !