Tighten permissions for workflow invocations.
Sharing a workflow with a user was previously sufficient to grant access to all invocations of that workflow. This isn't a huge problem since the information potentially leaking out was limitted to invocation counts, various encoded ids, and update times. Still I think no information about invocations should be avaialble as a result of sharing a workflow - and upcoming changes to Galaxy will result in much more information being made available via the workflow invocation API.
Update workflow invocation to_dict for recent collection workflow changes.
There may now be multiple WorkflowInvocationSteps for each WorkflowStep for steps that are mapped over collections - so to_dict creating a dictionary of this information indexed on order step is problematic because only one WorkflowInvocationStep will be represented per step. Instead now just returning a big list of all of the invocations - which contains all of the same information. This is a backward incompatible API change for the workflow invocation API.

Also update the input mapping stuff with logic for dealing with data collection inputs.
Refactoring out methods usable for downstream work on scheduling.