Remove redundant Java Function call() definitions

This should fix SPARK-902, an issue where some
Java API Function classes could cause
AbstractMethodErrors when user code is compiled
using the Eclipse compiler.

Thanks to @MartinWeindel for diagnosing this
problem.

(This PR subsumes / closes #30)
Merge pull request #100 from JoshRosen/spark-902

Remove redundant Java Function call() definitions

This should fix [SPARK-902](https://spark-project.atlassian.net/browse/SPARK-902), an issue where some Java API Function classes could cause AbstractMethodErrors when user code is compiled using the Eclipse compiler.

Thanks to @MartinWeindel for diagnosing this problem.

(This PR subsumes #30).