Developing for Drupal handbook -> Development tools improvements

When I ran the new contributors' BoF @ DrupalCon SF, the most-asked questions were about how to get a development environment up and running. There was a lot of analysis paralysis going on as would-be contributors tried to parse the huge amount of info available and decide what tools to use, then figure out how to set them up.

I'm working with sepeck, Heine, and realityloop to get OS-specific guides put together for a good basic dev environment. The same thing won't work for everyone, but by giving new devs a starting set-up that they can use, then audition replacements for tools that don't suit them, we can get them contributing sooner, and keep them from stalling in analysis paralysis for so long they give up and wander off.

I'll add the os-specific guides to the Development tools section (as their own sub-section) and then start thinking about how best to clean up and organize the rest of the "development tools" and "local server set-up" sections. Heads-up on ongoing efforts I should try not to step on the toes of, or ideas on how to make those sections more useful are needed and welcome :)

Note: Settled on "other" as the component since this is new docs, and clarification, and placement/navigation -- my brain gave up choosing between them. ;)

Marked novice because new contributors' ongoing feedback is needed to make sure we get this right.