a simple debug panel plugin

usage :
• upon loading the debug panel, it will be automatically registered under me.plugins.debugPanel
• you can then press the default "s" key to show or hide the panel, or use me.plugins.debugPanel.show() and me.plugins.debugPanel.hide(), or add #debug as a parameter to your URL e.g. http://myURL/index.html#debug
• default key can be configured using the following parameters in the url : e.g. http://myURL/index.html#debugToggleKey=d
the debug panel provides the following information :
• amount of total objects currently active in the current stage
• amount of the world's direct children drawn this frame
• amount of body shape (for collision)
• amount of bounding box
• amount of sprites objects
• amount of objects currently inactive in the the object pool
• memory usage (Heap Memory information is only available under Chrome)
• frame update time (in ms, averaged over the last 30 frames)
• frame draw time (in ms, averaged over the last 30 frames)
• current fps rate vs target fps
additionally, using the checkbox in the panel it is also possible to display :
• the hitbox or bounding box for all objects
• current velocity vector
• quadtree spatial visualization