Stop Inspector when all windows are closed

Stop Inspector when all windows are closed

Some apps(ex. hulu) will call window.close() when terminate, it will cause
'before-quit' invoked after 'window-all-closed'. In current logic, WRT stop
inspector when receive 'before-quit' event, but at this case, any wrt api
cannot be called successfully(I think it's related with window is closed firstly),
so stop inspector in 'window-all-closed' event, then RWI cannot stopped properly and
RWI port will be released normally

Change-Id: I8d3d46973cc1536bf6818c346d7c3ef43ed4be0a
Signed-off-by: liwei <wei90727.li@samsung.com>