Network id was not always included in cellId
* Some cellids were not fully qualified, so reuse of baseids in shared networks could give unwanted effects. This change will require devices to train cells again.
  - CDMA cellid did not include the networkid/systemid
  - GSM/WCDMA for some phones (likely older devices without LTE only) did not include the network operator.
* Error handling, checking every field individually.
Note: the check is >0 even if documentation says -1 is error. It is not uncommon with reporting 0 if unknown it seems, unknown should be handled as an error here.

This change should have been done before 1.0, but I did not feel this was investigated well enough then.
Merge pull request #60 from gerhardol/master.go

Network id was not always included in cellId

amazing job!