Remove the memory stuff from the spa API, we can do thing more simple
and efficiently if we always allocate buffers outside of the plugins and
only implement an alloc function on the node when it can do something
clever.
Move serialize code to the props/format/buffer code
Make it possible to copy a format and properties.
Serialize format and properties.
Simplify the properties by moving the unset-mask inside the property
structure. We can then also just use the index of the property as the
bit in the mask.
Work on stopping on disconnect
Add a memory reference helper struct that we can use to track the memory
in buffers and formats.
Remove custom property get and set, the default ones will work fine.
Custom ones are problematic when we want to serialize properties in
formats etc.
Deserialized Formats are now tracked in the memory pool and can be freed
if needed.
