XD-1536: Add ability to inject delimiter on pre-packaged jobs that deal with files.

Updated pre-packaged jobs to allow a delimiter to be injected where appropriate.
* Updated configuration of `filejdbc`, `hdfsjdbc`, `hdfsmongodb`, and `jdbchdfs`
 jobs to allow for the delimiter to be injected
* Added `BatchJobFiledDelimiterOptionMixin` to provide metadata around
 new delimiter option
* Updated `jdbc_tests` script to test the processing of a job using a tab
 as a delimiter.

Notes:

1. `unescape` does not belong in `BatchJobFieldDelimiterOptionMixin`, but I don't have a better place to put it right now (not familiar enough with the XD structure to know where to put a utility class like that…and it really belongs in Spring Core IMHO).
2. I know sed works differently from OS X to Linux.  I haven't tested the Linux version of the commas_to_tabs function.  I'm running on the assumption that Linux supports the `\t` notation for a tab character (which OS X does not).