Fixed lost params when battery empty

Fixing issue #4 : wake up period and threshold are restore from flash config to rtcMem when module is on charge

Records change after 3 consecutive measures.

** warning, bug discovered: wake up period and sensor threshold are lost when battery runs out **

The web interface has been improved.
Once the device has been initialized, the home page only shows the every day useful data, with a link to the settings page.
Threshold and wake up period are now stored in ESP rtc memory => no need to initialize full config when waking up, in order to save time and power.
But most important change is that a state change is only recorded after 3 consecutive measures, to avoir false positives.

In attachment of this release are binaries for french and english versions. They can be flashed to the modules using ETA and the excellent application ESP8266 Loader on Android.

Here are the build times displayed on the UI for each:
handMonitorEN.bin : Feb 16 2020 21:58:45
handMonitorFR.bin : Feb 15 2020 23:46:45