try fix travis builds, newer goveralls etc

Author: CpuID

.travis.yml

@@ -1,11 +1,7 @@
 language: go
 go:
-  - 1.7.3
-
+  - 1.8.1
 before_install:
   - go get github.com/mattn/goveralls
-  - go get golang.org/x/tools/cmd/cover
-
 script:
-  - go test -covermode=count -coverprofile=profile.cov -v ./...
-  - $HOME/gopath/bin/goveralls -coverprofile=profile.cov -service=travis-ci
+  - $HOME/gopath/bin/goveralls -service=travis-ci