fix line endings
WebUI: rename a few css classes, sort the properties by name
WebClientSocket.cpp: add line breaks to the produced html code
WebClientSocket.cpp: remove non existent css classes
Cosmetics.
"Play > Filters" menu: simplify the items' state handling.

This menu is dynamically built so there is no reason to use an extra function to set the state of its items. The states are now set correctly when building the menu.

Note that thanks to this change the new UI style is now used for the radio bullet.

This commit fixes ticket #1620.