Set humidity to 0 if value fails to parse

[jadonbaker]

Addresses issue #366

[cbrandlehner]

The pull request did not pass the XO checks but I will implement the change in a slightly different form.

Instead of
const currentHumidity = (value => isNaN(value) ? 0 : value)(Number.parseFloat(responseValues.hhum));
I will use
const currentHumidity = (value => Number.isNaN(value) ? 0 : value)(Number.parseFloat(responseValues.hhum));