2015-11-28  Alex Dunn  <dunn.alex@gmail.com>

        Improve version-to-list parsing

        * lisp/subr.el (version-regexp-alist): allow `.' as priority separator
        * lisp/subr.el (version-to-list): parse versions like OTP-18.1.5 correctly
        * lisp/subr.el (version-to-list): allow prefixed priority separators
        * test/lisp/subr-tests.el (ert-test-version-parsing): parsing tests