Readme updates on amplify core.

[ifandelse]

Additional usage examples in readme. These additions were prompted by https://github.com/appendto/amplify/issues/46. New examples explain subscribing to multiple topics in one subscribe call, and how to pass the "topic" as a param to the subscription callback. Also - the addition of the gitignore file at the root is to keep WebStorm from adding project metadata to the repo.

[scottgonzalez]

In general I don't like the idea of including how to build new features in the main docs. I'd much rather us write a full tutorial that walks through the logic and concludes with a full features solution. I'll leave this decision to the rest of the team. If we want to keep the topic-passing example in the readme, I'm ok with landing it after the code is updated.

[dcneiner]

I think in general I agree with you @scottgonzalez. The only thing that is a little different here, is that this is actually a common problem caused by the ability to subscribe multiple topics at once. Its a great feature (multiple subscriptions), but without the ability to see which topic fired, its somewhat limiting.

I think adding documentation (vs a tutorial) is a nice compromise if we can not add the actual feature. It addresses the need, but keeps the library simple.

[scottgonzalez]

We can link to the tutorial directly from the docs if your concern is purely about discoverability.

[ifandelse]

I wasn't aware that there was a separate place (another repo?) to write tutorials. I've put effort into explaining the multiple subscriptions because I've run into multiple developers using amplify that aren't aware of it. Second, I think the "how to get the topic from within the callback" is question that is going to come up over and over again - and considering that one developer expressed that he wouldn't use amplify unless this were possible, having information on how to do this somewhere accessible is wise, IMO. I will update the code formatting, etc. in case we end up wanting to merge this.

[scottgonzalez]

We would put it on the .delegate() blog and link to the article from the readme.

[ifandelse]

These changes should be sufficient. I vote we either just go ahead and kill this thing dead, or merge it.

[scottgonzalez]

Why did you switch to two functions? You're duplicating work on every subscription now.

[ifandelse]

@scottgonzalez the only duplication i see is the arg parsing that was happening in the wrapper function, as opposed to the subscribe call. Small change, IMO. I moved it.

[ifandelse]

Final ping - are we merging this or not?