gst/gstpreset.*: Change _get_preset_names API to return a strv with copies. Add _get_property_names to allow implemen...

Original commit message from CVS:
* gst/gstpreset.c:
* gst/gstpreset.h:
Change _get_preset_names API to return a strv with copies. Add
_get_property_names to allow implementations to filter and provide
good default implementation.
3 files changed