v4.0.0 not compatible with Scala 2.11

[pan3793]

> Task :xpark-scala:reportTestScoverage FAILED
[info] Found 1 subproject scoverage data directories [/Users/chengpan/IdeaProjects/xpark/xpark-scala/build/scoverage]

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':xpark-scala:reportTestScoverage'.
> scala.collection.JavaConverters.asScalaBuffer(Ljava/util/List;)Lscala/collection/mutable/Buffer;