README.md: Upgrade OneWire to 2.3.5

Use OneWire library version 2.3.5 (latest as of the moment).

Signed-off-by: Leon Anavi <[email protected]>

anavi-thermometer-sw.ino: Reduce ClientID length

Reduce the ClientID length and try to keep it below 23 bytes.

According to MQTT protocol version 5.0, the MQTT broker must allow
23 UTF-8 encoded bytes for ClientID. Some brokers MAY allow a
longer ClientID:
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901059

This commit fixes GitHub issue #43:
#43

Reported-by: Antonio Tapiador <[email protected]>
Signed-off-by: Leon Anavi <[email protected]>

anavi-thermometer-sw.ino: Display I2C sensor data

Show data such as barometric pressure and light on the mini OLED
display if appropriate I2C sensor modules are detected: BH1750
for light and BMP180 for barometric pressure.

Suggested-by: Albert Pauw <[email protected]>
Signed-off-by: Leon Anavi <[email protected]>

anavi-thermometer-sw.ino: Append 5 chars to AP

Append the last 5 characters of the machine ID to the Access Point
(AP) name for initial configuration. This simplifies the initial
configuration process and prevents WiFi mismatches if you launch
several units of ANAVI Thermometer for the first time at the same
time. In similar cases with this feature (almost always) each of
them will create AP will different name. There is still a very
small chance that there might be units with the same last 5
characters of their machine ID. The same approach has been already
implemented for ANAVI Gas Detector, ANAVI Light Controller and
ANAVI Miracle Controller.

Signed-off-by: Leon Anavi <[email protected]>

Merge pull request #21 from cederlys/fix-ota-with-arduinojson6

Fix OTA upgrades for ArduinoJson 6

Initial unstable version