Wiki documentation update

[dlmiles]

Please take 10 minutes to review these Wiki pages I started. Unfortunately much of the knowledge to fill them in is only know by tdiesler and the source code history.

https://github.com/tdiesler/gravia/wiki/Manifest-Metadata
https://github.com/tdiesler/gravia/wiki/Version-History-&-Compatibility

If possible please take 10 minutes to check the information is correct and update with any new information to assist.

If some of the facts as not exactly known then please provide a link in the wiki to key source code files that would allow someone to easily find the information to help establish the facts, so the documentation is correct.

Thanks