This first counts ports (using the builtin slv2 functions to do so
rather than manually as before), then creates descriptors for each port
and finds all port groups. Only then are pad templates created (towards
using group information for creating multi-channel pads).
- Separate gstsignalprocessor into a separate library (not sure if this
is in the right place, but it works for now anyway)
- Create LV2 element based on LADSPA element, port most discovery
functionality
