Fix for V8 disables optimization for dispatch

[Hypercubed]

I posted this issue on the master (millermedeiros#67) but submitting a PR here because I can build and test this version.

I haven't checked the actual performance impact of this change vs. previous but suspect enabling optimization is better.

[mhofman]

Interesting. It's baffling V8 disables optimizations when copying arguments in this quite common way, especially since named args are not used at all in this function.

You might want to open a pull request on jvmartins/js-signals instead. This repo incorporates their build system changes as well as a change in how dispatch itself works (by catching and rethrowing exceptions asynchronously)

[Hypercubed]

Here is a list of "optimization killers": https://github.com/petkaantonov/bluebird/wiki/Optimization-killers . Not my work so I don't know how much this impact performance.

I made the PR because it appeared to be the most ahead. It would be nice if there was a true active fork of js-signals.

[Hypercubed]

From what I can tell there is a significant difference: http://jsperf.com/shotgun-js-vs-js-signals/4