bigbluebuttonbn plugin CSS fonts use relative paths

Situation
The bigbluebutton plugin uses custom fonts in it's styles.css file.
Relative paths are used to specify the bigbluebutton fonts. This does not follow the moodle's guideline on adding custom fonts.

On installations with custom paths, this causes the loading of the fonts to fail.

Expected behaviour

Font should load properly.

Actual behaviour

Fails to load the font if path to styles.php varies.

Solution

Correct relative paths used in styles.css to follow moodle's recommended approach.