Adds confirmation for window closing
Made suggested changes
Added missing dispose call
Changed LoadoutFrame to use VetoableChangeListeners instead of
InternalFrameListener for detecting closing of the frame. This allows
the caller of `frame.close()` to receive the cancellation of the close
which in turn allows `desktop.closeAll()` to determine if it was
successfull.
Merge pull request #154 from EmilyBjoerk/frameCloseFix

Adds confirmation for window closing (#49)