o-b-merge-params function was not allowing whitespace around the '=' sign.

At some point it might be useful (to me at least) to clarify our rules
regarding whitespace, and make guidelines for using " \t\f\n\v\r" et
al (and [:space:]?).

lisp/org-babel.el

@@ -531,8 +531,8 @@ parameters when merging lists."
 		    (case (car pair)
 		      (:var
 		       ;; we want only one specification per variable
-		       (when (string-match "^\\([^= \f\t\n\r\v]+\\)=\\([^\f\n\r\v]+\\)$" (cdr pair))
-			 ;; TODO: When is this not true? Can there be whitespace around the '='?
+		       (when (string-match "^\\([^= \f\t\n\r\v]+\\)[ \t]*=[ \t]*\\([^\f\n\r\v]+\\)$" (cdr pair))
+			 ;; TODO: When is this not true?
 			 (setq var (intern (match-string 1 (cdr pair)))
 			       ref (match-string 2 (cdr pair))
 			       vars (cons (cons var ref) (assq-delete-all var vars)))))