Fix loading as browserified in AMD style

[inetfuture]

I use this library with browserify, then generate the dist for others to use. One of them tried to load it with requirejs with shim config, it failed, because this library take over the whole module.

I'm not sure if my change is appropriate, just tell me if you think it's not, thanks.

[coveralls]

Coverage decreased (-0.74%) to 91.85% when pulling f371dd69b85bd4f2894c9ea27208f55ea57b6c35 on inetfuture:patch-1 into 792fdab75cb771514de0f9c902b9352b718a3a8b on mathiasbynens:master.

[inetfuture]

@mathiasbynens please look into this

[stackOverMind]

Thank you @inetfuture ,I have the same problem,I think your patch works for me