More intelligent fall back when not expanding.

Rather than calling `indent-for-tab-command', do a search for a binding of tab
in any active minor mode map (aside from `smart-tab-mode'), then search the
major mode's binding, then the global binding. This allows a fallback to the
mode-specific binding of tab.

Signed-off-by: Dan Hackney <chrono325@gmail.com>

smart-tab.el

@@ -74,15 +74,24 @@ the region or the current line (if the mark is not active)."
       (if smart-tab-using-hippie-expand
           (hippie-expand nil)
         (dabbrev-expand nil))
-    (smart-indent)))
+    (smart-tab-default)))
 
-(defun smart-indent ()
+(defun smart-tab-default ()
   "Indents region if mark is active, or current line otherwise."
   (interactive)
   (if mark-active
       (indent-region (region-beginning)
                      (region-end))
-    (indent-for-tab-command)))
+
+    (call-interactively
+     (or
+      ;; Minor mode maps for tab (without smart-tab-mode)
+      (cdar (assq-delete-all 'smart-tab-mode (minor-mode-key-binding "\t")))
+      (cdar (assq-delete-all 'smart-tab-mode (minor-mode-key-binding [(tab)])))
+      (local-key-binding "\t")
+      (local-key-binding [(tab)])
+      (global-key-binding "\t")
+      (global-key-binding [(tab)])))))
 
 (defun smart-tab-must-expand (&optional prefix)
   "If PREFIX is \\[universal-argument] or the mark is active, do not expand.