Ticket #12 : removed the previous hack-ish parallax layer code

Todo :
* implement the CSS -like repeat field (Ticket #124)
* update tutorial (Ticket #100) and documentation (html/github)
* clean-up any remaining messy code
* wait for the next Tiled release with official Image Layer Support
Ticket #124: added the "repeat" field for later reference (when working offline)
Added proper documentation for the `ratio` property
Stop using local copy of the library, and refer to parent directory for the last build
Ticket #100 : replaced obsolete "paralax" layers stuff by the new Image Layer

TODO :
* Update screenshots in the tutorial when an OSX version is available
(only windows nighty build are available for now)
Ticket #124 : fixed `repeat` variable scope
Ticket #100 : added missing ImageLayer Property screenshot (thanks @parasyte) and other documentation improvements
Ticket #100: update screenshot with something better matching the tutorial content (thanks Parasyte)
Ticket #100 : added back the missing Image Layer
Ticket #124 : add `repeat` property handling
Merge branch 'ImageLayer-cleaning' of https://github.com/obiot/melonJS into ImageLayer-cleaning
Merge remote-tracking branch 'origin/master' into ImageLayer-cleaning
Merge remote-tracking branch 'origin/master' into ImageLayer-cleaning

Conflicts:
	examples/alexkidd/data/map/zone1/1.tmx
	examples/alexkidd/data/map/zone1/2.tmx
	examples/alexkidd/data/map/zone1/3.tmx
	src/level/TMXTiledMap.js
Remove this old example too, to ease with a new merge later
re-applied lost changes during last merge
Merge remote-tracking branch 'origin/ImageLayer-cleaning'

Conflicts:
	examples/tiled_example_loader/index.html
	examples/tiled_example_loader/style/bullet.png
	examples/tiled_example_loader/style/content.png
	examples/tiled_example_loader/style/footer.png
	examples/tiled_example_loader/style/graphic.png
	examples/tiled_example_loader/style/link.png
	examples/tiled_example_loader/style/logo.png
	examples/tiled_example_loader/style/menu.png
	examples/tiled_example_loader/style/menu_select.png
	examples/tiled_example_loader/style/search.png
	examples/tiled_example_loader/style/style.css
Updated changelog based on the last Image Layer branch merge
updated changelog
re-applied lost changes during last merge