await, mongoose!

The biggest update since... well, the last update.

+ additions

• slabbot me is now a thing!
  • A basic exp system. Some exp per message.
    • You get exp for each message, with a cooldown of 5 seconds.
    • The amount of exp you get depends on the last time you sent a message.
      • look at this graph
  • Also tracking command usage. Stats are cool.
    • Oh yeah, and now a MongoDB instance is required. Defaults to connecting to mongodb://localhost:27017.
• slabbot about is better.
  • Displays some stats (commands used, top commands)
  • Uses an embed now. Hopefully looks a bit nicer.
• slabbot shutdown does what it says on the tin.
  • This is an owner only command - only runs if the user's ID is in config.json.

~ other changes

• The cooldown message now displays cooldowns in seconds. (3642ms → 3.64s)
• Some commands now have much longer cooldowns:
  • me has a rate limit of 2 uses / 30s
  • about has a rate limit of 1 use / 30s
• More general code cleanup. Mostly removed some console.log() stuff.

It's been a long, long time since the last update, but... I think I'm starting to get the hang of some of this stuff. So... that's cool!
As always, never expect any updates, because I'll probably end up abandoning this again for another month. Or something like that.

Thank you for following development of slabbot!