Check addresses with Geocoder before sending to the API

[dektar]

https://developer.android.com/reference/android/location/Geocoder.html

avoids things sent to the civic API which it recognizes as valid, like https://5calls.org/issues/?address=%0A https://5calls.org/issues/?address=f https://5calls.org/issues/?address=7

[dektar]

Also, enable autocomplete!