String concatenation expressions.
trivial? function for expressions and bracketing for non-trivial components in pretty printing.
Moved expressions over to epagoge (https://github.com/ramsay-t/epagoge)
Moved all Z3 components to epagoge
Updated travis.ml file to include OTP 17.1
Removed Z3 tests. Moved to epagoge
Removed travis path fix script (used by Z3).
Fix mix hex problems for travis.
More travis mix fixing.
Travis elixir fix.
Travis mix deps.get