Deeplearning4j: Remote UI and spark conflict issues: Need better documentation

[tomthetrainer]

Spark conflicts with our UI forcing the need for a remote UI. This is covered rather well (I think) in the docs under distributed training, however it seems they could be re-organized or clarified in some way. Opening this issue for a general revue and clarification of the UI documentation to verify it is well covered in a central easy to find location.

I will close https://github.com/deeplearning4j/deeplearning4j/issues/2617

And refer all discussion to this issue.

[beatngu13]

Unfortunately, the UIExample crashes for the same reason. How's one supposed to fix this?

Moreover, why does the doc explicitly mentions that the remote UI functionality "will require the deeplearning4j-ui_2.10 or deeplearning4j-ui_2.11 dependency"? Doesn't step one of the tutorial says it's a prerequisite anyway?

[clavvis]

I tried AnimalsClassification from dl4j-examples and had the same error as is described in #2617.
I dont need Spark. So I removed this dependency:

      <groupId>org.datavec</groupId>"
      <artifactId>datavec-spark_${scala.binary.version}</artifactId>

from my pom.xml and example is working.

Is any possibility not remove Spark dependency and "say" (set): Now I dont want to use Spark?

Thank you.