a couple empty classes in an attempt to thwart circular importing

conflicts and circular imports

helper.py; added from_string constructor to CapabilityStepType

CapabilityService, CapabilityInfo, CapabilityQueue, and
CapabilityEngine; updated some schema and interfaces

CapabilityExecutions

DB setup)

capability info

capability launcher; finished implementation of prototype capability
schema; began implementing capability services

the architecture we want; updated Capability and CapabilityRequest in schema.py

product_interfaces.py, and workflow_interfaces.py

comments and reorganized the order of the classes

architecture documentation

implemented service classes; also updated some interfaces

present in the archive eventually

changes

methods based on the architecture diagrams; copied null capability
implementation from wksp0

wf_monitor to use new amqp_helpers setup; updated wf_monitor tests;
updated WorkflowEventSchema to accept a string in the timestamp field
instead of a datetime (we could probably change this, but this is how
it's set up for now)

originally going to use a singleton pattern but ran into issues with
that)