Consider adding GO15VENDOREXPERIMENT support

[kardianos]

In 1.5 the go command will read the environment variable GO15VENDOREXPERIMENT. If enabled, it will use the local "/vendor/" folder for dependencies. This replaces the need to manage GOPATH variables as dependencies can be fetched directly into the vendor folder and resolved there when built. This allows the GOPATH to not be modified. The contents of the vendor folder can be ignored.

Will you consider supporting this approach?

[gkristic]

I still have to take a more detailed look at that, to be honest, but yeah... I'll consider if it's worth including. Thanks for bringing it up.

[gkristic]

I'm changing to a VC-specific Github account. @gkristic-vc will take it from here.