Documention on Integration Tests is missing and add them to CI

The integration tests aren't run on the Travis CI, @allburov do you run them against your own Artifactory Instance?

I know that the API isn't available without an Artifactory license, I've just sent them a support request asking if they could also add API scope to the free Artifactory version, otherwise I don't think it will be possible to run integration tests against via. Travis.

Seems [go-artifactory](https://github.com/lusis/go-artifactory) is getting an Artifactory Cloud instance sponsored for their CI tests.