New features, docuementation, and Compatibility update to Entities 0.3.0-preview.4

Changes

• Added SingletonConvertGroup and SingletonPostConvertGroup to simplify managing order for conversion systems.
• SingletonConvertSystem now all by default run in SingletonConvertGroup
• All SingletonChanged* variant systems now run in SingletonPostConvertGroup
• Bumped required Entities version to 0.3.0-preview.0, as there was little compatability problems between 0.2.0-preview, but this seems to have fixed ConvertToEntity issues.

Fixed compatibility with entities 0.2.0-preview.18

This provides minimum compatibility fixes for the latest entity packages.

Tests have been updated and checked for compatibility.

Added Samples

• Added 3 samples based on various user requests:
  • Config File Loading
  • Simple Database Example
  • Simple World Converter
• Each sample comes with a README.md file explaining various parts of the sample.
• Added some more base classes to derive from to reduce boilerplate.
• Removed the need to write a blob reference copy when using blob singletons, we now serialize/deserialize with an in-memory stream to create a new copy with minimal code.

Documentation Fixup

Fixed links in manual.md, singleton-converter-system.md, and TableOfContents.md.
Fixed some code formatting in singleton-converter-system.md.

First comprehensive release

Refactored and solidified Singleton API, rewrote to be more data-oriented, less reliant on MonoBehaviour Subclasses.

Fixed several bugs and design holes in the ScriptableObject -> Blob Conversion API.

Added full test coverage for both hybrid and pure DOTS code.