fix our go paths!

[jenmei]

• [x] add $GOPATH/bin to our main paths
• [x] on jen-mei's computer, fix the folder structure on disk to match go/src/github.com/oaktown/calliope . also copy over gitignored local files
• [ ] on judy's computer
• [x] on sarah's computer
• [x] fix paths on all the import statements in our files
• [x] check in vendor

[jenmei]

Bill thinks we should checkin vendor, but the dep faq says that there are pros and cons of both.

On the one hand, I don't really like the idea of checking in 3rd party code if it can be reliably re-created.

On the other hand, unlike npm or ruby gems, the code isn't published to a registry – people just pull things directly from repos, which, unlike registries, are completely under the control of the authors. So if an author deleted their repo, it would cause all kinds of problems.

I guess all things considered, checking in is a better guarantee. But I think if we do that we should be careful of mixing up vendor changes and our commits.