gtags.el mouse-2 and mouse-3 key bindings

[Jani Nikula]

I'm not particularly happy with gtags.el binding mouse-2 and mouse-3 for 
gtags mode. I find breaking the middle mouse button paste quite intrusive. 
I'd suggest introducing some kind of configuration for that, even if this 
can be worked around e.g. with the following in .emacs:

(add-hook 'gtags-mode-hook
          (lambda ()
            (define-key gtags-mode-map [mouse-2] nil)
            (define-key gtags-mode-map [mouse-3] nil)
            ))


Otherwise, thanks for an extremely productive tool!

BR,
Jani.