Fix a small problem in clang builds due to namespaces and symbol lookup
correct output language bug with --dump-to
Remove old miplibtrick from arith static learner
new miplib pass, works for 1 or 2 vars
extended miplib trick to 6 vars, should work on pp miplib examples now
new option for doing top-level miplib substitutions (or not)
Merge from mdeters/miplib branch (commit 'ce7c485182902ae43871057185095f71f74a8a58')
Some cleanup of miplib regressions and options