[BUG] SWADE new round bug fix

[kckaiwei]

This fixes:
#45

Some refactoring was done on the function handling combat updates as well.

Usage:

No real changes, will properly update when a new combat round is done in SWADE. Note that there may be a short moment where the marker jumps to the correct new actor. It's a limitation and not fixable with my current knowledge/additions to the SWADE system

Tech notes:

While SWADE does emit a socket signal:

game.socket.emit('system.swade', { type: 'newRound', combatId: this.id });

I'm having difficulty picking it up with a Hooks.once('ready' for some reason. I'm not sure whether there's no cross module support in foundry or if I'm doing something wrong, but the lack of foundryvtt documentation hasn't cleared it up for me.

There's also no hook fired when a new round is created (the function that SWADE overrides to reshuffle initiative), with that said, I've had to resort to hooking into the renderCombatTracker hook, which would get fired after each turn update + each round update. It's not the most ideal solution, considering how there are multiple emits for that hook, but its the best that can be done without a proper hook, and no access to the socket.

The logic checks for the SWADE system specifically, so normal functionality won't be affected.