cleanup output dirs before starting pipeline
Merge pull request #62 from uci-cbcl/wbiesing/minor-cleanups-for-driver

cleanup output dirs before starting pipeline
change setAsCopy() to use getThisReadSequence() and getThatReadSequence()
use getKmerLetterLength() instead of getKmerBytesLength()
check toString() in readHeadInfo
change getEdgeList() to getEdgeMap() in readKeyValueParser
small teaks and prepare for test new graph building
Merge branch 'genomix/fullstack_genomix' into nanzhang/ray-genomix

# By Jake Biesinger
# Via Jake Biesinger
* genomix/fullstack_genomix:
  cleanup output dirs before starting pipeline
recover it VkmerList initially and prepare for refining it
a tweak