Merge pull request #2 from davidlmorton/master

Minor clarifications and name changes
be more specific about workflow callbacks
Merge pull request #1 from mark-burnett/petri-callbacks

Initial spec for petri callbacks
change "put token" URL
Merge pull request #3 from mark-burnett/petri-color-group-put

petri: add color group to put token url
workflow: specify workflow structure in json
workflow: cancelling a wf needs to cancel sub-wfs
lsf: add note about polling job status
Merge pull request #4 from mark-burnett/json-workflow

workflow: specify workflow structure in json
Merge pull request #5 from mark-burnett/notes-from-backlog-review

Add some notes from JIRA backlog review
Use parallel-identifiers instead of operation-ids
First attempt at unifying GET /v1/workflows/(id)
workflow: use PATCH to upload outputs
workflow: parallel_identifier -> execution_id
workflow: add sample for GET /v1/executions/(id)
workflow: POST subworkflows to an execution
workflow: usage examples for GET /workflows/(id)
workflow: add operation data to execution GET
workflow: whitespace
workflow: add GET /v1/executions endpoint