re-implement org-reload to work with compressed and compiled-only installations

* lisp/org.el: Safe-guard agains the accidental loading of compiled
  versions of org-loaddefs (these must be bogus).  Make sure that
  installations that do not have the source files (only .elc) and/or
  compress the files (.el.gz, .elc.gz) are correctly treated when such
  files must be loaded.  If it is necessary to exclude compiled files
  from loading, temporarily bind load-suffixes to only (".el") instead
  of forcing a literal ".el" suffix (which doesn't work with
  compressed files for some functions).  Re-implement org-reload to
  reload based on features that are currently loaded rather than files
  it finds in whatever directory since it is impossible to know if
  they were loaded from there.  Indicate whether the reloading was
  successful or encountered an error in the message area.

lisp/org.el

@@ -78,7 +78,8 @@
 (require 'find-func)
 (require 'format-spec)
 
-(load "org-loaddefs.el" t t)
+(let ((load-suffixes (list ".el")))
+  (load "org-loaddefs" 'noerror nil nil 'mustsuffix))
 
 ;; `org-outline-regexp' ought to be a defconst but is let-binding in
 ;; some places -- e.g. see the macro org-with-limited-levels.
@@ -233,11 +234,14 @@ When FULL is non-nil, use a verbose version string.
 When MESSAGE is non-nil, display a message with the version."
   (interactive "P")
   (let* ((org-dir         (ignore-errors (org-find-library-dir "org")))
-	 (org-install-dir (ignore-errors (org-find-library-dir "org-loaddefs.el")))
+	 (save-load-suffixes load-suffixes)
+	 (load-suffixes (list ".el"))
+	 (org-install-dir (ignore-errors (org-find-library-dir "org-loaddefs")))
 	 (org-trash       (or
 			   (and (fboundp 'org-release) (fboundp 'org-git-version))
-			   (load (concat org-dir "org-version.el")
-				 'noerror 'nomessage 'nosuffix)))
+			   (load (concat org-dir "org-version")
+				 'noerror 'nomessage nil 'mustsuffix)))
+	 (load-suffixes save-load-suffixes)
 	 (org-version (org-release))
 	 (git-version (org-git-version))
 	 (version (format "Org-mode version %s (%s @ %s)"
@@ -19991,44 +19995,46 @@ Your bug report will be posted to the Org-mode mailing list.
   "Reload all org lisp files.
 With prefix arg UNCOMPILED, load the uncompiled versions."
   (interactive "P")
-  (require 'find-func)
-  (let* ((file-re "^org\\(-.*\\)?\\.el")
-	 (dir-org (file-name-directory (org-find-library-dir "org")))
-	 (dir-org-contrib (ignore-errors
-			    (file-name-directory
-			     (org-find-library-dir "org-contribdir"))))
-	 (babel-files
-	  (mapcar (lambda (el) (concat "ob" (when el (format "-%s" el)) ".el"))
-		  (append (list nil "comint" "eval" "exp" "keys"
-				"lob" "ref" "table" "tangle")
-			  (delq nil
-				(mapcar
-				 (lambda (lang)
-				   (when (cdr lang) (symbol-name (car lang))))
-				 org-babel-load-languages)))))
-	 (files
-	  (append  babel-files
-		   (and dir-org-contrib
-			(directory-files dir-org-contrib t file-re))
-		   (directory-files dir-org t file-re)))
-	 (remove-re (concat (if (featurep 'xemacs)
-				"org-colview" "org-colview-xemacs")
-			    "\\'")))
-    (setq files (mapcar 'file-name-sans-extension files))
-    (setq files (mapcar
-		 (lambda (x) (if (string-match remove-re x) nil x))
-		 files))
-    (setq files (delq nil files))
-    (mapc
-     (lambda (f)
-       (when (featurep (intern (file-name-nondirectory f)))
-	 (if (and (not uncompiled)
-		  (file-exists-p (concat f ".elc")))
-	     (load (concat f ".elc") nil nil 'nosuffix)
-	   (load (concat f ".el") nil nil 'nosuffix))))
-     files)
-    (load (concat dir-org "org-version.el") 'noerror nil 'nosuffix))
-  (org-version nil 'full 'message))
+  (let* ((org-dir     (org-find-library-dir "org"))
+	 (babel-dir   (or (org-find-library-dir "ob") org-dir))
+	 (contrib-dir (or (org-find-library-dir "org-contribdir") org-dir))
+	 (feature-re "^\\(org\\|ob\\)\\(-.*\\)?")
+	 (remove-re (mapconcat 'identity
+		     (list
+		      (if (featurep 'xemacs) "org-colview" "org-colview-xemacs")
+		      "^org$" "^org-infojs$" "^org-loaddefs$" "^org-version$")
+		     "\\|"))
+	 (lfeat (append
+		 (sort
+		  (delq nil (mapcar
+			     (lambda (f)
+			       (let ((feature (symbol-name f)))
+				 (if (and (string-match feature-re feature)
+					  (not (string-match remove-re feature)))
+				     feature nil)))
+			     features))
+		  'string-lessp)
+		 (list "org-version" "org")))
+	 (load-suffixes (if uncompiled (reverse load-suffixes) load-suffixes))
+	 (load-misses ()))
+    (setq load-misses
+	  (delq 't
+		(mapcar (lambda (f)
+			  (or
+			   (load (concat org-dir f) 'noerror nil nil 'mustsuffix)
+			   (unless (string= org-dir babel-dir)
+			     (load (concat babel-dir f) 'noerror nil nil 'mustsuffix))
+			   (unless (string= org-dir contrib-dir)
+			     (load (concat contrib-dir f) 'noerror nil nil 'mustsuffix))
+			   (and (load (concat (org-find-library-dir f) f) 'noerror nil nil 'mustsuffix)
+				;; fallback to load-path, report as a possible error
+				(message "Had to fall back onto load-path, something is not quite right...")
+				f)))
+			lfeat)))
+    (if (not load-misses)
+	(message "Successfully reloaded Org\n%s" (org-version nil 'full))
+      (message "Some error occured while reloading Org features\n%s\nPlease check *Messages*!\n%s"
+	       load-misses (org-version nil 'full)))))
 
 ;;;###autoload
 (defun org-customize ()