nodes: stop using 'class' as function argument name
single blob commit for prototype routing
introduce the pa_goto_if_fail macro
fixing pa_sequence_insert() to not break the linked list
prototyping the logical routing with sink-inputs
intoducing module-murphy to prototype/test routing modules
Allocate the pa_sink_input object early

This allows us to get rid of the PA_NODE_UNDER_CONSTRUCTION state.