cwl-util 0.8 -- major expression refactor tool refactoring

• fix errors in graph_split, added test @mr-c
• improve CLI for graph_split.py #38 by @altairwei
• clean up image pullers @mr-c
• update CWL v1.0, v1.1 and v1.2 parsers @mr-c
• docstring everywhere! @mr-c
• Added a CONTRIBUTING guide @mr-c

cwl-utils 0.7 - CWL v1.2 final + $schemas support

$schemas support is courtesy of @leipzig ; thanks!

cwl-utils 0.6

create codeseq analysis @mr-c
regenerate parsers (#26) @illusional
bump schema-salad version (to >=7 <8) @illusional

cwl-utils 0.4

• update v1.0 and v1.1 parsers with optional field support (#15 @illusional)
• freshen testing setup (@mr-c)

cwl-utils 0.3

add v1.1 parser @mr-c
add script to replace ExpressionTools with CommandLineTools @mr-c

cwl-utils 0.2

new utility: graph_split.py (a $graph splitter) @mr-c
docker_extract.py:
Allow to pull images with Singularity #4 @khillion
Support both Singularity 2.6.1 and 3.x
image_puller.py: Change replace charcter #9 @manabuishii

hello world

0.1

add some basic tests