Wrong activity type should be a User Exception

[phact]

https://github.com/engineblock/engineblock/blob/master/eb-api/src/main/java/io/engineblock/util/SimpleServiceLoader.java#L46

[phact]

Which is not that simple because eb-util doesn't import eb-core. This promises to become a major problem with dependencies.

Why don't we use an Exception from java.lang? Maybe something like UnsupportedOperationException?

[jshook]

I've logged this in the new consolidated project as nosqlbench/nosqlbench#3, and added details on implementation that should clarify how to deal with the dependency issues.