Added simplified version of SRWholeGenome.

- Added `SRWholeGenome_Simplified.wdl` which uses a simplified version
  of the HaplotypeCaller workflow to run faster.  This was accomplished
  by removing the scatter by interval.  This workflow will not scatter
  by interval when performing variant calling.  This is OK for small
  genomes / organisms.
- Added `HaplotypeCaller_Simplified.wdl` which performs germline variant
  calling on an input bam file without any scattering.

Author: jonn-smith