Player and Server blacklisting

[JustAlittleWolf]

Fixes #26 by adding a configurable array of players and servers to blacklist from showing their numeric ping. Can be configured as a string array in the config. Example:

{
  "autoColorPingText": true,
  "renderPingBars": false,
  "pingTextColor": "#A0A0A0",
  "pingTextFormatString": "%dms",
  "blacklistServers": [
    "play.mccisland.net"
  ],
  "blacklistPlayers": [
    "Steve",
    "Herobrine"
  ]
}