PipeWire 0.2.2

- Various fixes to memory handling
- Fixes for shutdown
- v4l2 fix enumeration of frame intervals
- Make the daemon stop when the setup commands fail
- Improve safety of hooks
- Update stream API to more future proof version
- Add more options to stream API such as scheduling in the
  main thread and automatic mapping of buffers
- Add version file and macros to check compile time and
  runtime versions of pipewire
- Future proof some structs
- Increment API version and .so version

Work is ongoing in the work branch that features a completely new
scheduling method that will enable audio support. Some of these
API changes are backported in this branch.