Added level and charging event

level and charging properties now fire notification events and allow listening for changes.

Implemented hybrid mode to support Polymer 1.x and 2.x

-) Bower dependencies updated
-) Switched to iron-demo-helpers in demo page
-) Added inline demo to README.MD

Rotate enhancement

Added --battery-icon-rotate style, which enables easy rotation of the battery-status-icon.

Samples:

/* Battery icon is rotated and drains from left to right. */
--battery-icon-rotate: rotate(270deg);

/* Battery icon is rotated and drains from right to left. */
--battery-icon-rotate: rotate(90deg);

Display charge / discharge time in tooltip

New features are:

• Display remaining charge / discharge time in paper-tooltip
• Customize tooltip style
• Customize tooltip position

Bugfixes:

• No icon was displayed when charge level went below 20 %

Style improvements

battery-status-icon now comes with following new features:

• Battery color changes based on level
• Predefined colors can be customized
• Icon size can be changed

0.0.3: Merge pull request #6 from Protoss78/Issue#3

Added:
-) web-component-tester test suite
-) iron-component-page

Initial release with Navigator.getBattery() API support

In this initial release the battery-status-icon is now able to autodetect the various battery states by using the new Navigator.getBattery() API. It uses Polymers iron-icons to display the battery level and whether it is charging or not.