Cross compiling RvH using an unreleased version of Rusoto

[matthewkmayer]

https://github.com/matthewkmayer/rusty-von-humboldt needs a Rusoto feature that isn't in a release yet. It also needs to cross-compile from OSX to Linux to run on AWS.

Make a walkthrough describing the problem and how to do it:

• cross-compiling openssl is painful
• Docker can't toss in a folder in a parent dir
• make a Dockerfile that brings in Rusoto from GitHub and creates a Linux binary we can use for deployment
• why this approach vs letting TravisCI do it

[matthewkmayer]

Not gonna happen.