Upgrade to Meetup API v3

[specious]

The Meetup API now has many v3 endpoints in addition to the v2 interface.

Currently this app is relying on @neektza's fork of the rMeetup ruby gem for interfacing with the Meetup API. I absolutely appreciate all the work that went into that project.

As there have been no recent commits on that project and it only covers a part of the v2 API, perhaps it makes sense to look around for what ruby gems might support the latest API endpoints.

Incidentally, finding a better way to access the Meetup API should resolve security concern #2.

[specious]

I'm taking a close look at: mike-vascelli/rubeetup

[specious]

Superseded by #9.