v0.3.0

Another experimental release. Rainbow Gum is almost on par with Logbacks core features with only rolling files not implemented yet.

• Caller info for line numbers, method name etc is now an opt-in option
• Fix #56
• Default Async logger was very broken in 0.2.0 and now it is working but I would not consider it production ready yet.
• Initial benchmarking using TinyLog's benchmark shows promising results #50

Full Changelog: v0.2.0...v0.3.0