After review with Ben, Lauren, and Peter, simplify the ProvONE model:

- Collapse InputPort and OutputPort to just Port
- Change the hadPort property to hadInPort and hadOutPort (for Usage and Generation)
- Collapse outputsTo and inputsFrom properties to hasLocation
- Change isPartOf to wasPartOf (to be consistent with other property tenses)

The rational is that the object properties and class names were semantically redundant.  The hasInPort and hasOutPort properties of Program already indicate flow direction, and so we modeled it the same way with Usage and Generation using hadInPort and hadOutPort.
Merge branch 'master' of https://github.com/DataONEorg/sem-prov-design