Refactoring webaudio backend to avoid firing play event.
adding states for the webaudio backend
fixing syntax here
fix to let seeking occur after track finish
adding set state function, firing a progress event of 1 on finish.
Merge branch 'master' into seekto
only changing state if it's not currently in that state
Merge pull request #276 from naomiaro/seekto

Seekto
code style; update build