Naming issue when artifacts are correct in wu run

[dherre3]

Description:
Passing valid arguments to wu run, valid as in having a correct configuration of artifacts. A problem occurs when two of the artifacts have the same name.
Behaviour:
Throws a javascript error relating to an array
Expected Behaviour
Let the user know that two artifacts cannot have the same name.

Note of specific case:
Accidentally using both an experiment and an environment with the same name.