* wesnoth-mode.el: Remove cl requirements.

* wesnoth-mode.el: Remove cl requirements.
  (wesnoth-element-completion): Removed gensym usage.
  (wesnoth-determine-wml-version): New function.  WIP.
  (wesnoth-completion-available): Removed.
  (wesnoth-complete-macro): Replaced `find' usage.  Requires wesnoth-update.
  (wesnoth-build-completion): Replaced `find' usage.
  (wesnoth-check-element-type): Replaced `remove-if-not' usage.
  (wesnoth-line-number-at-pos): New function.
  (wesnoth-check-output): Use it.
  (wesnoth-check-wml): Require wesnoth-mode.  Replaced `find' usage.
  (wesnoth-mode): Show version used in the mode-line.

* wesnoth-update.el: Removed cl requirements.
  (wesnoth-default-version, wesnoth-wml-version): New custom variables.
  (wesnoth-files-in-dir): Replaced `remove-if' usage.
  (wesnoth-cfg-files-in-dir): Replaced `remove-if-not' usage.
  (wesnoth-handle-file): Replaced `subseq' usage.
  (wesnoth-append-tag-information): Replaced `find' usage.
  (wesnoth-output-path): Fixed a bug where a variable was passed as an
  argument, instead of the variable's symbol.
  (wesnoth-update): Iterate over all versions defined in `wesnoth-wml-version'.
  No longer output `provide' form to file.