Proposed change to Pipmak's grabbing

[Aidan G. <wgs...@no...>]

Hello,

I have writtien a patch for Pipmak that changes the way it grabs the
window-manager input as follows:
* It no longer automatically when the mouse enters the window.
* It no longer ungrabs the mouse when the mouse is run against the window edge.
* Pressing Ctrl+Alt toggles the grabbing.
* When grabbing is on, a message is displayed in the window title that tells
the user how to get his mouse back.
* All calls to SDL_WM_GrabInput() have been changed to call a new function in
Pipmak itself: pipmakGrabInput().
* pipmakGrabInput() handles changing the title to add the message mentioned above.

I wrote this patch, because I always found the auto-grabbing a bit akward, and
I would like some feedback from the other Pipmak users on this.

  --Aidan