Implemented trimmomatic recipe with test. Created get_test_input_path and subdirs of input; used in TestFilterLastal.
Don't require executability for Broad unix trimmomatic.
Fixed issue 12: Tool.install tries remaining methods after success.
Merge pull request #13 from broadinstitute/irwin-issue12

Fixed issue 12: Tool.install tries remaining methods after success.
Merge remote-tracking branch 'origin/master' into irwin-taxon_filter
Merge pull request #14 from broadinstitute/irwin-trimmomatic

Irwin trimmomatic
Created class DownloadScript. Made some changes to DownloadPackage.
Merge branch 'irwin-taxon_filter' into irwin-DownloadScript
Merge pull request #15 from broadinstitute/irwin-DownloadScript

add DownloadScript, subclasses DownloadPackage