waitFor() semantics

[mattmccray]

Currently the waitFor method is pretty much the same as the stock Facebook one:

this.waitFor([ AStore.dispatchToken, OtherStore.dispatchToken ])

I'd like to make the dispatcher entirely an implementation detail. The waitFor method can extract the dispatcherTokens itself.

To me, this reads much nicer:

this.waitFor( AStore, OtherStore)

Or, if you feel strongly about passing an array instead of iterating the arguments:

this.waitFor([ AStore, OtherStore ])

What do you think? I'd be happy to create a PR if it's something you think fits with alt's vision of Flux.

[goatslacker]

That sounds good. If we can make it backward compatible I'm all about that PR.