Skip unit tests, run Ecukes tests for each Emacs version.
Remove unused mocker package.
There is no recipe for Ert.
Bundle Ert for Emacs-23.
Omit third argument to delete-directory

which is not supported in Emacs 23.
Change content type on el files.
Send content-length in fake ELPA server.
Use `elnode-http-return' with content length to avoid trailing ^M.
Update command is not supported in Emacs-23.
Skip Emacs-23 tests by default.
Remove redundant semicolons
Merge pull request #56 from rejeep/unit-tests-to-ecukes

Skip unit tests, run Ecukes tests for each Emacs version.

Due to limitation of old package.el bundled with carton
(carton-package.el), `carton update` is not supported in Emacs 23.
Test for Emacs 23 is taken care by adding tags.

Note that even though Emacs 23 test passed in Travis, failure on local
machine is reported by @tkf and @rejeep.