Entitas-csharp: Polish Unity Inspectors

[sschmid]

Entitas comes with a bunch of helpful Editors and Inspectors for Unity.
They kind of look good already, but there can be done much more to make them feel even more integrated into Unity.

If you guys have ideas which parts can be visually more appealing or let me know. Doing suggestions with PRs much appreciated :)

[sschmid]

Playing around with internal Unity Editor code... it's both awesome and a pain :)

[sschmid]

[sschmid]

[sschmid]

Ha, found the native Play and Skip Buttons :)

All sections can be collapsed / expanded

[sschmid]

Coincidence? :) #ECS

[sschmid]

Drastically simplified EntityDrawer, got rid of all hacks and EntityDrawer.Initialize().
Replacing components with object pooled components on GUI.changed which enabled me to remove ITypeEqualityComparer completely and simplify ITypeDrawer