refactored 01-06 to match recent live workshops

Re-organized and expanded the first 6 lessons to match our delivery at TGAC and UW, and merging in the most recent material from [Mozilla Science Lab](http://mozillascience.github.io/instructorTraining/).

Changelog:

 - `01-intro`: most of this content has found a home in more appropriate places; I left the text commented out in `01-intro.md` in case anyone wants to recyle it; if not, just delete the whole comment block. My intro and setup for the first half of the workshop is under 'Goals & Questions'.
 
 - `02-concepts`: now contains the concept mapping, memory and expertise material found at http://mozillascience.github.io/instructorTraining/knowledgeAndExpertise/index.html; previously, was titled as concpet mapping, but instead contained information about understanding computing; this content has been moved to `12-understanding.md` until we decide where to put it.
 
 - `03-motivation`: untouched for now.
 
 - `04-design` through `06-peerInstruction`: these correspond, in order, to the content developed at http://mozillascience.github.io/instructorTraining/designAndAdaptation/index.html; some of this was scattered around in `07-classroom.md` and `11-design.md` previously; this new structure reflects the order we've actually been teaching it in. The peer instruction content was repeated twice (@gvwilson's way and my way) - I've taken a run at merging the two (they were very similar anyway).