support images in mp4chaps

not tested
switch from localStorage to Cookies for @martinhering (https://github.com/podlove/podlove-web-player/issues/95)
(this is a test - (I will test it, but predict far more problems with cookies))
fix mp4chaps image support, update readme.md/txt
Merge pull request #1 from podlove/master

update to 98b5f45
release 2.0.12 is comming soon
make
fix mp4chaps code
Merge branch '2.0.12'

Conflicts:
	podlove-web-player/header.txt
	podlove-web-player/podlove-web-player.php
	podlove-web-player/readme.md
	podlove-web-player/readme.txt
	podlove-web-player/settings.php
	podlove-web-player/static/podlove-web-player.css
	podlove-web-player/static/podlove-web-player.js
Merge pull request #2 from podlove/master

2.0.12
fixes missing chapter title or image