Travis go 1.10 (#313)
Travis go 1.10 (#313)

* travis: add Go 1.10.x

* travis: add Go master

This CL adds testing against Go master, but it won't mark the PR as
failed if something goes wrong against master.
Also, the PR won't wait for master to complete.

go-mangos/mangos,gdamore/mangos,go-mangos/mangos