Fix indentation.  Replace spaces with tabs.

* clojure-mode.el (clojure-font-lock-keywords)
(clojure-display-inferior-lisp-buffer, define-clojure-indent)
(clojure-char-at-point, clojure-fill-docstring): Fix indentation.
Set `indent-tabs-mode' to `nil' locally in clojure-mode.el.