Update quick-start guide to use sample of 20 Kenyon cells
Remove unhelpful tests
Tidy quick-start guide
Add instructions for huge score matrix
Fix to use knitr to produce vignette
use package extdata dir as data download folder
sidestep a bug in knitr that fails to produce output dir for rgl snapshots
don't run load_fcdb(neuron) - it's not there at the moment
Merge branch 'master' of jgit:flycircuit

* 'master' of jgit:flycircuit:
  Fix to use knitr to produce vignette