Modernize the development environment

This is a maintenance release to modernize the development environment. There are no changes in the code of the module so these updates should not affect the functionality of the module.

• Get rid of Grunt, use native npm scripts instead to run the linters.
• Update all dependencies to the latest versions.

Security update (CVE-2019-10744)

This is a maintenance release to fix CVE-2019-10744 in the lodash developer dependency . This change does not affect the functionality of the module.

Styling DOM elements

• ADDED: Support for styling the DOM elements via CSS classes.

Added humidity support

• ADDED: Support for displaying humidity value, if data is provided by the sensor.