New variable for icon font-size

on screens smaller than 480px
Mixin iconfont-button: Replace text-shadow for opacity

Leave the light text-shadow effect only on open, therefore active tab
icon.
Responsive layout for control-buttons #1

First solution: Display both lists in a row on wide screen, in two rows
on smaller screens.
Create container for timecontrolbar
Create container for toggle bar
Styles for timecontrol bar and toggle bar wrappers
Change markup for toggle bar and control bar #2

- Append toggle bar to wrapper element instead of controlBox.
- Both lists are nested within a wrapping container now.
- Both wrappers have a new class ‘bar’ for general bar-styling, that
will be extended by class ‘togglebar’ and ‘controlbar’.
Create class 'bar' to define general styling for controls

Import file _controls.scss to main scss file.
Styling for control bars 'togglebar' and 'controlbar'.

Responsive behavior already included!
Merge remote-tracking branch 'upstream/controlbar-changes' into dev

Mediaelement was deleted and togglebar added at the same line.

Conflicts:
	src/sass/podlove-web-player.scss
minor fixup