Bug fixes

Updates:

• uses apache-airflow==1.10.12 & cwltool==3.0.20200710214758
• outputs CWL related logs into separate files
• supports simple scatter
• supports literal file inputs

Tested on cwl-v1.1 conformance test from Oct 7, 2020

• total: 253
• excluded: 2 (due to common-workflow-language/cwl-v1.2#51)
• failed with known reason:
  • 2 (due to common-workflow-language/cwl-v1.2#52)
  • 5 (due to #43)
  • 12 (due to #44)
• success rate: 90%

Reference: SDDA Sprint 1