pax-properties-coproduct

This crate acts as a blank - a dummy dependency that allows projects to bootstrap their initial compilation, later replacing this blank with an application-specific PropertiesCoproduct.

In other words: every project needs a PropertiesCoproduct in order to compile, but that PropertiesCoproduct cannot be known until the project is initially compiled. This blank allows the first compilation to occur.

The Cargo patch mechanism is how this blank is intended to be substituted for an application-specific PropertiesCoproduct. The ExpressionTable is expected to be patched in by the same mechanism.