Cow 1.0.0

* Fix OCaml 4.02 compatibility by not exposing a `Location` module
  in syntax extensions to avoid a namespace clash. We now rename them
  to `Xml_location` and `Css_location` and pack those instead.
* Fix BSD compatibility using `$(MAKE)` instead of `make` (since the
  GNU make binary is actually `gmake` on Free/Net/OpenBSD).
* Reduce the verbosity of the build by default.
* Travis: Add OCaml 4.02 and OPAM 1.2.0 tests