Driver for Icarus Essence

Fixes #1226304 [request of support for new device](https://bugs.launchpad.net/calibre/+bug/1226304)
pep8
Keep position when deleting tags in the tag editor

Fixes #1226093 [[Enhancement] Tag editor should remember place](https://bugs.launchpad.net/calibre/+bug/1226093)
Update Liberation

Fixes #1226391 [Private bug](https://bugs.launchpad.net/calibre/+bug/1226391)
Merge branch 'kovidgoyal/master'
Make icon rules composable.