And keeping only most basic SMS

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

- fixed int/uint warning
- added functions to get local IP address with esp8266
- fixed local ip fxn for xbee
- removed extra test builds
- set travis to build all modems in tests

I realized they're not as usable on their own as I expected.