Clean up / fix Imp and Logic chapters
Finished Smallstep
Fixed bug in Auto

So apparently someone had written case instead of Case, messed some
things up, fixed that
Added unicode support to SfLib

After going back to Agda for a bit, I'm really tired of how ugly Coq
is.  Hopefully this will do a bit to fix that.
Types chapter

Types make things so much easier
Started STLC chapter