Make allocparams into pod objects. This makes it easy to serialize,
copy, create and intersect them.
Add convenience macros for properties
Add helper function to collect object properties.
Use a POD for the format body. This allows us to more easily build
and copy the formats.
Remove obsolete code to make video and audio formats.
Use SpaVideo/AudioInfo to keep track of formats. Make functions to parse
the format into the structures.
Update plugins
