Jordan Russell's patch (3rd of several). We now don't call TermOut()

if the PuTTY window has the mouse capture (i.e. a drag-select is in
progress). This means you can drag-select at your leisure without
the screen contents wandering around providing you with a moving
target. Likewise dragging the scrollbar to find a piece of history
in the scrollback.

git-svn-id: svn://svn.tartarus.org/sgt/putty@1517 cda61777-01e9-0310-a592-d414129be87e