v1.0.0-pre3: Changed Placeholder format and other changes

Breaking changes

• Changed placeholder pattern from {<text>} to ${<target> <type>}. See the Placeholders Section on the wiki.
• {playerVersion} is now ${player protocol}

Added

• Added new placeholders
  • ${players online} for all online players.
  • ${players max} for total amount of players that can join.
  • ${player name} for the Player's name (Requires the player to have joined before and defaults to ?)
  • ${player version} for displaying the MC version. Only works on Velocity.
• Players joining the network will be cached alongside their IP address for the ${player name} placeholder