Refactor meetup api

[caseywatts]

I love the work @uncompiled did on this! :D In this PR I'm just cleaning up the code some, functionality isn't much changed.

I've extracted it into parts:

• meetup_cards.html file now has the guts of the operation
  • templates (mustache) are in their own place, no string concatenation required
  • the mustache put-this-here logic & loop
  • made a presenter class (just wrapping two methods @uncompiled wrote)
• API call is still in the Meetup class.
  • I'm considering either using this package for a better API interface or refactoring the code to accept some arguments like meetup group id

I'm pretty excited about this refactor because now we have a drop-this-in kinda web componenty thing going on. This is something another group could drop in and it would just about work for them! Maybe extracting configuration to an object would be a helpful next step.

[caseywatts]

I went ahead and just extracted configuration to an object, that's easy enough :)

[benjaminoakes]

This is going a good direction. I think we should avoid window.onload in favor of $(document).ready(fn) or $(fn) though. That's a next step to consider. :smile: