[Issue]
  Damage points are always same.

[Cause]
  The canvas for EditText is cached at Player.setCanvasRenderableCache(), associated with its character-id,
  However, if multiple instances of EditText that share the same character-id are created, and each of them has a different text value, the cache is overwritten.

[Fix]
  Modified the EditText's code that calls Player.setCanvasRenderableChache() to store an object rather than CanvasRenderable.
Merge pull request #63 from kuu/master

[BugFix] Fixed a bug of EditText's renderable cache.