Setup the new flycheck-ocaml syntax checker
Update default opam commands to newest syntax

Newer versions of opam don't do argument parsing of the first argument
after `opam config exec` so everything needs to be passed as separate
arguments in the shell (i.e. unquoted).
Merge pull request #754 from RadicalZephyr/ocaml-flycheck

Ocaml flycheck
Merge remote-tracking branch 'bbatsov/master'

* bbatsov/master:
  Update default opam commands to newest syntax
  Setup the new flycheck-ocaml syntax checker