update to use Control.GArrow instead of GHC.HetMet.GArrow
bundle preview.sty to avoid versioning headaches
partial implementation of KappaAbs/KappaApp in Coq code
very rudimentary support for feedback in GArrowTikZ
fix bugs in BiGArrow
use -fsimpleopt-before-flatten in sanity checks
Makefile: use a for-loop to compile sanity checks
add "sanity" target to Makefile
add -fflatten and -funsafe-skolemize flags
update demo
start using type-family-based GArrow classes
add Demo.hs
add Makefile target for tikz demo
add examples/Makefile