Removed faster <--> better slider

Was no longer necessary with the asynchronous cancel
WIP
Extracted entire round management into separate view.
Results view is tabbed
Display player list in UI
Abstracted storage location
Player list is loaded from xml file instead of CSV.

Can import from CSV, and add new entries manually.
All players are now stored in xml, with their
"Currently Present" status. Should now be able to administer
the entire app without closing it.
Able to permanently delete players.

- Player pairings are fixed up for departing and arriving
  players joining the current round
Rename table header