Got MSISDN reading from SIM working!

Some things probably still dependent on my device. Probably won't
work on newer SIMs (USIMs), but that should be just a matter of
instantiating the correct *Records class so that the different
file path gets used.

Still requires SuperUser and SEEK telephony patches. Tested on
Sony Xperia Z1 Compact stock, Android 4.4.4.  I believe the approach
will work on CyanogenMod 11, just needs the UID changed.