Grouped Logging feature

[jwoertink]

When you log a bunch of asynchronous code, it gets logged out of order which leads to some confusing logs. To go along with luckyframework/lucky#950 (comment), one thing we could do is queue up everything that needs to be logged, then log the queue all at the same time.

This could also be along the same lines as #38 where using dexter becomes a queue center for logging and special formatting. Then you can use the standard Crystal Log for lower level control.