Allows more flexibility downstream

Also some minor documentation and naming changes for consistency.

And keeping only most basic SMS

Set default alphabet for sendSMS

problem was new lines, not time.

Otherwise was going into an endless reading loop because user code only asked for a short part of the total amount of data sent.

Also fixed the "isNetworkConnected" for ESP8266

Also shorted time between checks in "isNetworkConnected" for all modems