ticket #108: fixed mouse position detection when the viewport offset is not (0,0)
updated changelog (again)
 Updated tutorial to use the new map background color picker (instead of specifying a custom map property)
Merge pull request #154 from agmcleod/master

Added volume option to audio.play()
Minor changes and clean-up on the last commit
added a angle/angleTo function

https://groups.google.com/forum/?fromgroups=#!topic/melonjs/DDtfE02Mk2Y
Fixed me.Font horizontal alignement feature

this is no inline with the bitmap font implementation
added a `levelCount()` function
added a `distanceToPoint()` and `angleToPoint()` function
added a function that returns the current animation frame index
revert these changes, as it breaks auto-scaling under certain conditions
added in animation speed option