Simplify build scripts

[philwinder]

Current problem:

• Too complex
• Too slow (runs gvt for every build)

I like the build in container philosophy, but maybe it's not required. Devs have to manage their deps to to development anyway. Consider removing build container?

Also see #34

[khyew]

Check in the vendored dependencies in the vendor/ folder. This will eliminate the step of fetching/pruning dependencies from the Internet for each build, which constitutes the majority of the time in the build step.

[drubin]

I think this demo should work as close to the real world as possible.

I think with #50 and if we improve #32 it will be more than fast enough.