v1.15

Happy to welcome our newest collaborators @Carpetsmoker and @bhcleek 👋

Please checkout the changelog for this release: https://github.com/fatih/vim-go/blob/master/CHANGELOG.md#115---october-3-2017

Do you want to support vim-go? Checkout the fully optional donation option, a way to support vim-go's ongoing development directly: https://www.patreon.com/fatih