Go 1.10 support (#223)

* Update Travis CI to use latest Go releases

* Fix go vet issues for Go 1.10

Starting in Go 1.10, the `go test` command now automatically runs `go
vet`. This commit fixes two issues flagged by vet that cause `go test`
to fail.

* Fix gofmt issue for Go 1.10

Go 1.10 introduced a small formatting change with comments in empty
multiline slice definitions.  This commit attempts to move the offending
comment in such a way that all version of gofmt will agree on its
location.

* Remove go-vet from test.sh

Starting in Go 1.10, the `go test` command automatically runs `go vet`,
so we don't need to run `go vet` explicitly from within test.sh.

Fixes #222

test.sh

@@ -23,9 +23,6 @@ function git_clone() {
 # Remove potential previous runs
 rm -rf src test_program_bin toml-test
 
-# Run go vet
-go vet ./...
-
 go get github.com/pelletier/go-buffruneio
 go get github.com/davecgh/go-spew/spew
 go get gopkg.in/yaml.v2