Patch that adds import and export jobs to the hbase mapreduce MR driver.
Export does like Jon's writing out to sequence files.
Import reads in from said sequence files.
These classes are more inline w/ the the 0.20.0 MR idiom (and not unnecessary reduce, etc.).
Also fixed RowCounter so no longer an output dir.
Fixed tableinputformat so no longer need to specify columns (if no columns, then all columns).
Changed some of the util so it can take null classes.. sometimes need this (e.g. above imports/exports).