Add perf package to the VM.
FEAT: add default dark styling + intro.
ENH: intro 'meat' done, building mostly done as well.
FEAT: add code_organization + finding your way.
Clean up index. Try to load local remark first.
Show where to find headers.
Add concepts and ufuncs sections.
Consistently use dark slide for topic announcement. Minor formatting fix.
Fix side-header formatting (too long).
ENH: intro and build numpy sections done.
Ufunc content update.
Merge branch 'stefanv/mid-flight'

Conflicts:
	slides/building_numpy.md
	slides/index.html.tmpl
	slides/intro.md