v0.8.1

0.8.1: hand each step its place in the record

Every action a runner executes receives DATATORCH_PROJECT_ID,
DATATORCH_RUN_ID, DATATORCH_PIPELINE_ID and DATATORCH_STEP_ID, set by the
runner from the dispatch and never inherited from the outer process. The
same facts are available to an action's own templates as run.*. An
action that works for the project it runs in no longer needs a project
input, which is what lets a pipeline fork into another project unchanged.