[WIP] Issue 835 speech warnings

Settings have been implemented.  Now the features need to be implemented:

- [ ] Solar Activity Warning
- [ ] Wind Speed
- [x] 400ft ceiling exceeded
- [ ] low signal strength
- [x] lost signal
- [ ] low battery
@squilter if you're using android studio, you might not be seeing `context.getString(...)` as AS collapse the call into the string it's supposed to return. 

`context.getString(...)` is used to provide the first parameter to `prefs.getString(..., ...)`.