Add a new option to configuration file: FORCEEXIT, like SILENTEXIT
but ignores the client count. Unsaved client work may be lost with
this option but it is useful if you want no dialogs.
Add description of this new keyword to XWinrc man page
Also fix grammar of the exit confirmation dialog warning to be correct
when there is only one(1) client connected.
Also rearrange yacc tokens to one per line to make future merges
easier
Also amend default system.XWinrc so that SILENTEXIT is on by default
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
