Add Support for ES6

[wruth]

Spur IOC breaks for fat arrow function syntax in ES6. For instance, I got this error when I attempted to run the ES6 code directly without babel transpilation:

/Users/wruth/workspace/ot-microsite-address-validation-service/node_modules/spur-ioc/src/Util.coffee:11
      params = fn.toString().replace(/\n/g, ' ').replace(/_at_/g, '').match(/function\s+\w*\s*\((.*?)\)/)[1].split(/\s*,\s*/);
                                                                                                         ^

TypeError: Cannot read property '1' of null
  at Util.parseDependencies (/Users/wruth/workspace/ot-microsite-address-validation-service/node_modules/spur-ioc/src/Util.coffee:9:46)
  at Function.Dependency.resolvableDependency (/Users/wruth/workspace/ot-microsite-address-validation-service/node_modules/spur-ioc/src/Dependency.coffee:15:29)
  at Injector.ContainerManagement.addResolvableDependency (/Users/wruth/workspace/ot-microsite-address-validation-service/node_modules/spur-ioc/src/ContainerManagement.coffee:16:38)

I believe this is a consequence of Util.js looking for the String 'function' in parseDependencies(), and not being able to find it in these cases.

[acolchado]

@wruth Thanks for reporting. Yeah, I ran into that when making the changes and documented it, but can't recall where.

I will document the work around and share out in the documentation. Since there is a pretty straight forward workaround, we will not be prioritizing it over the other work scheduled for the libraries. It will be a focus soon enough, but I don't have an ETA for that.

cc @ssetem Any ideas/suggestions?

[ssetem]

yeh right now the top module.exports=function(dep1, dep2){ ... needs to remain

Have been using spur-ioc alot recently, not much advantage changing the top declaration to es6 syntax

[acolchado]

@ssetem Yeah. That's what I initial thought, just didn't seem to document.

[morewry]

I think it's useful in unit tests. See #31 and spur unit tests, where dependencies often get set to this.Dependency in order to make them available from a beforeEach in a later spec. I'd also personally expect to be able to use any valid JavaScript syntax. Just my 2 cents.