V2.5

- changed UI to make configuration faster and integrate templates
better
- added template download from remote server
- sync now simplified (single file only) with ability to set sync date
- added BD sensor for list of BT devices connected at any moment
- added TE sensor for template used for recording
- changed Wifi handler to return empty readings if no WiFi is found
- fixed bug in AZ, RO, PI sensors
- added ability for sensors to disappear in failure cases (e.g., if
connection to heart monitor failed)
- show template being used in measurement window