As suggested by Ederson de Souza. https://groups.google.com/forum/?utm_medium=email#!msg/delve-dev/W_SfC3i9tf0/MY4QWaZOCgAJ
Additionally removes test code / html / txt / etc from vendor dir.
Use godeps to vendor dependencies and the normal go toolchain, with GO15VENDOREXPERIMENT=1 set to properly vendor dependencies for reproducible builds.