Merge pull request #156 from agmcleod/master

new `animationspeed` parameter for the `addAnimation()` function, allowing to specify a different animation speed per animation
documentation fix/clarification
missing comma !
gives a proper error message if the specified id does not exist
contributor list update
version bump to 0.9.6 and copyright information update
Simplified the TMX implementation by removing useless base classes and related inheritance

and additionally, it also clarifies the documentation, and should help
with ticket #140
ticket #110 : added a `getCurrentTrack()` function
ticket #110 : added a global volume control

and also added a volume parameter to the `me.audio.playTrack` function
(to be in line with the `me.audio.play` one)
ticket #110 : stop the current playing track when `me.audio.disable()` is called
rewrote the `me.audio.playTrack` function to reuse the `me.audio.play` one
ticket #110 : added mute(all)/unmute(all) audio functions
ticket #15 : first pass update
Use a typed array (if supported) when decoding Base64 encoded tilemap

with typed arrays supposing to use less memory, this should help a bit
when loading/switching levels (assuming Base64 is used !)
Fixed tiny issues in the foreground layer
rewrote these two functions with better self-caching
Prefer`responseXML` when available + fixed issue #158
Optimized the use of the TMXRenderer object, by reusing when possible a default one

as most map/layer have anyway the same structure
fixed missing comma
Fixed several small documentation issues