Using `go install` instead of `go build`

as the latter discards artifacts when multiple packages are specificed
without an `-o` flag, which is the case when passing `./...`.
Simplifying by doing both steps via `go get` per community feedback
Merge remote-tracking branch 'upstream/master' into go-installs-with-go-install

Conflicts:
	spec/script/go_spec.rb
Merge remote-tracking branch 'upstream/master' into go-installs-with-go-install

Conflicts:
	lib/travis/build/script/go.rb
	spec/script/go_spec.rb
Merge remote-tracking branch 'upstream/master' into go-installs-with-go-install

Conflicts:
	lib/travis/build/script/go.rb
Merge pull request #107 from meatballhat/go-installs-with-go-install

Using `go get` instead of `go get -d` + `go build`