Add dependency on scopt
Improve VeriT parsers

Now there is a trait, as usual in the Scala combinator parsing library
Refactor draft proof exporter
Add draft CLI for proof compression
Change command line interfaces
Move Axiom and CutIC out of lk.scala
Remove inefficient computation of ancestor relation
Remove inefficient computation of ancestor relation
Clean CutIC
Add UncheckedInference

This will be useful to parse VeriT's theory inferences.