Automatically parse and build key/value when in objects without having
to prefix the key with ":"
Automatically build control/value when in sequence without the "."
prefix.
Remove the builder with key/pod, taking a reference to the stack built
temporary pods is not allowed in c++. We can use the varargs version
with the same convenient syntax.
Remove the parser "*" option, it is unused.
Improve spa_pod_builder_add_* and spa_pod_parser_get_* and make them
look similar.