add focusedWindow

set on events, but not yet used for fullscreen
overload getWindowSize to accept a winNo

splits update part of getWindowSize() into updateWindowSize(), which
makes more sense semantically, and easier to split into overloaded
methods.
overload getWidth/getHeight with winNo arg
overload getScreenSize with winNo arg
overload getWindowPosition with winNo arg
implement getWindowMonitor
overload getWindowMode with winNo arg
protect against null pointers on window methods 

standardises windowNo argument name
remove unnecessary elses in getScreenSize

will fall through to final return statement if any conditions are false
overload setWindowPosition with windowNo arg
overload setWindowTitle with windowNo arg

add setWindowTitle to winManager API
overload setWindowShape with windowNo arg
add setWindowShape to WindowManager
add setWindowTitle and Shape to example
override set/toggleFullscreen with windowNo arg
OS X, all fullscreen windows hide menu bar UI
add set/toggle fullscreen to WindowManager
add fullscreen toggling to example
add setWindowPosition to WindowManager
closeActiveWindow becomes closeFocusedWindow