Avoid Option while generating call site

This is an update on https://github.com/apache/spark/pull/180, which changes the solution from blacklisting "Option.scala" to avoiding the Option code path while generating the call path.

Also includes a unit test to prevent this issue in the future, and some minor refactoring.

Thanks @witgo for reporting this issue and working on the initial solution!

Author: witgo <witgo@qq.com>
Author: Aaron Davidson <aaron@databricks.com>

Closes #222 from aarondav/180 and squashes the following commits:

f74aad1 [Aaron Davidson] Avoid Option while generating call site & add unit tests
d2b4980 [witgo] Modify the position of the filter
1bc22d7 [witgo] Fix Stage.name return "apply at Option.scala:120"