All scripts that are generally useful across all builds have been moved
into `pulumi/scripts`. These changes clone that repository and retarget
the various scripts to their new location.
For some tools we used, like `dep` and `gometalinter` we were just
calling `go install` which caused us to pick up whatever was in `HEAD`
at that time. Now, we move to a model where we install fixed versions,
which will change per milestone.
While doing this, I changed the way our .travis.yml file runs
everything to move as much as possible out into scripts and do so in a
way that allows us to share as much common logic across our
repositories.
