* Revamping module development docs - work in progress
* Refurb of developing modules content continues.
* Developing modules refurb work continues
* Continued refurb of developing modules content. Work-in-progress.
* Ibid
* Dev guide content refurb continues - WIP
* Ibid.
* Removed reference to old extras module repo
* Tweaks
* Removed some non-intro material; added link to github module PRs.
* Incorporated review feedback from @gundalow and @tkuratomi; fixed some links; renamed '*contributing' to '*checklist'
