Rebuild abella.cma from .ocamlinit when needed
Reducing the lexing DFA table size by a lot

Goes from

316 states, 24001 transitions, table size 97900 bytes
3291 additional bytes used for bindings

to

58 states, 779 transitions, table size 3464 bytes
1743 additional bytes used for bindings
New option "types" to show types of variables
unfold_named: existentially close over residual logic variables

Fixes #33
Unification failures in unfold_named are tactic failures

They were incorrectly being treated as successes.
Fix to nominal constant detection

Uses real regexp now, so constants like nabc123 are not considered
to be nominal
unfold_named: raise clause over support
Removed the ~ notation