Changes to some of the dev documentation

[fu]

With denise's help (the bulk of this was from her really!), we've made major changes to the dev-facing wiki documentation for clarity.

Among other things:

• merged multiple/redundant pages and sections

• improved linking

• (hopefully) reduced the complexity of paths through the wiki for someone just getting started

The biggest change is to Dev Getting Started, which is now greatly expanded, with a much clearer flow, and more focus on someone totally new to DW/development. The resources for someone more experienced have been moved to Dev Quick Start .

The contents of Version Control have been merged with Newbie Guide: How To in Git and the latter is the canonical page for git info -- though now I'm tempted to go rename it to Version Control because it's shorter. Git How To? ;)

Git instructions in some pages have been updated to be much simpler with a pointer to the appropriate section in the git commands in case that's needed.

And the Directory Structure has been expanded to cover more subdirectories.

Beginner Dev Checklist needs some more effort to pull it apart: plan is to integrate it into other pages as appropriate and then get rid of it (since it's not sufficiently different from Dev Getting Started to warrant its own page)

Would appreciate if you poked around through the various pages and let me know if there's anything still left unclear, or if you're aware of similar pages that can be merged into these existing ones!