Fix another global namespace polluting syntax error.
Ticket #147: Fix `viewport.shake()`

- Now works with any size map.
- Will no longer actually "scroll" the map position.
- Always resets to original position when shaking completes.
- Simplified code.
- Now accepts `duration` argument in *milliseconds* instead of frame count.
Remove an unused var
This check isn't necessary
fixed "non-string" arguments
Fixed font position (following the recent changes)
Cleaned-up the gfx asset directory
Update correct characters list for making custom font
Add unlockKey function that allow to unlock key manually
Merge pull request #180 from DblK/master

Update Font listing character
updated contributors list
Fixed other functions when non -string values are passed

Not the cleanest way, but interesting jsperf result :
http://jsperf.com/convert-to-string-bj/2
Fix me.ImageLayer.ratio on Firefox & Opera

- When me.ImageLayer is smaller than viewport, and ratio < 1, moving the viewport left will cause the viewport position to be a negative number.
- Negative image sources work fine in Webkit, but fail in Mozilla and Opera.
Update all metatiles to add the top ladder image
Fix problem with ladder
Add new function getEntityByProp
Add example documentation to `me.state.change()`
Move metatiles32x32.psd to a new directory.
Minor change to another doc comment.
Update Makefile to work on Windows
Merge pull request #183 from DblK/getEntityByProp

Add new function getEntityByProp