temporarly disable :exhaust to fix :e
temporarly disable :exhaust to fix :e

Reopens #94; the book talks about using :e to edit files, and having :exhaust in the command trie breaks this. We need to figure out a better way to disambiguate (#90)

GaloisInc/cryptol,GaloisInc/cryptol,TomMD/cryptol,ntc2/cryptol,GaloisInc/cryptol,TomMD/cryptol,TomMD/cryptol,TomMD/cryptol