Use SM2 multiple formats url feature

[iuriizharkov]

Thank you for the great component, does its job really well.

I was trying to specify the url parameter in multiple formats as mentioned in
http://www.schillmania.com/projects/soundmanager2/doc/#smsound-url and unfortunately failed to do that.

My first guess was updating the propTypes in the source code. So on the line 246 instead of

  url: _propTypes2.default.string.isRequired,

I put

  url: _propTypes2.default.oneOfType([
    _propTypes2.default.string,
    _propTypes2.default.array
  ]).isRequired,

The test showed that the code, in fact, does not seem to cope with the multiple formats. I was trying ogg and wav like so <Sound url={["blah01.ogg", "blah01.wav"]} /> and it worked for the first file in the array. Then I renamed the first file on the server and the second wasn't loaded.

Could you please help me making it work.