Update index.htm to display 4 decimals for sp gravity.
Update settings.htm tooltips to indicate allowable values for some
settings.
Update DNS/IP address validation and mDNS validation functions in
http_server.cpp & wifi_setup.cpp.
Fix comment in tiltHydrometer.cpp to match current implementation.
Update index.htm to display 4 decimals for sp gravity. Update settings.htm tooltips to indicate allowable values for some settings. Update DNS/IP address validation and mDNS validation functions in http_server.cpp & wifi_setup.cpp. Fix comment in tiltHydrometer.cpp to match current implementation.