Refactor ImportTsv

ImportTsv is a little goofy.

• It doesn't use the Tool,Configured interfaces like a mapreduce job should.
• It has a static HBaseAdmin field that must be initialized before the intended API of createSubmittableJob can be invoked.
• TsvParser is critical to the default mapper implementation but is unavailable to user custom mapper implementations without forcing them into the o.a.h.h.mapreduce namespace.
• The configuration key constants are not public.