changed default sequence length to extract to 200
minor pep8 fix in test_scripts
Merge branch 'master' of github.com:ged-lab/khmer into update/extract-long-seqs

Conflicts:
	ChangeLog
fixed ChangeLog per @mr-c
Merge pull request #486 from ged-lab/update/extract-long-seqs

updated extract-long sequence to extract 200 bp sequences by default