Percentage while sliding, options to hide title and buttons

[nevries]

Hi @Deejayfool , this is a great project many people are using, so am I ;) There was some functionality I was always missing that I add with this PR:

• When you grab the slider, a percentage div is shown next to it that changes while dragging the slider, when you drop it, it will disappear. It is enabled by default but can be disabled by property.
• There is a new option "hide" for title_position to get rid of it completely (nice for room dashboards when the room has only one cover)
• There is a new property to not show the buttons at all.

Would appreciate if you would accept my changes, but happy to discuss.