Kenny/sm gatk

[kennyworkman]

• Replace skipped rules with Ellipsis. Supports rules nested in conditionals where previously an empty block was produced.
• Patched parser to generate compiled code for workflow.include calls Compiled workflow.include should carry print_compilation keyword snakemake/snakemake#2469
• Detect use of conda keyword and install in image. This effectively supports wrapper/conda keywords.
• Support for multi-ext keyword

[ayushkamat]

@maximsmol should also look