Merge pull request #97 from vezzi/devel

More bug fixing and --retry_failed option for piper runs
Merge pull request #7 from NationalGenomicsInfrastructure/devel

Merge from vezzi
Move things around a little; committing prematurely as I can't work on Nestor
add qc workflows
note engine-specific code that must be fixed/abstracted
Create engines submodule
Change imports to reflect submodule restructuring
Only process IGN samples
Merge pull request #99 from mariogiov/devel

Uppdatering
Merge branch 'NGI_devel' into devel