OTHER: s/_xmms_stream_type_new/xmms_stream_type_new/
OTHER: Remove commented out code from streamtype.c.
OTHER: Add xmms_object_destroy_notify.

A convenience function for managing xmms_object_t objects inside
GLib based data structures.
OTHER: Change goal_formats from GList to GPtrArray.

GPtrArray benefits from being refcounted which makes memory management
more flexible since a caller can decide if the xform chain should free
the memory or not. Also unifies the goal_formats variable names to 
stream_type_goals, stream_type, or supported_stream_types.
OTHER: Split out chain creation into xform_chain.c.
OTHER: Add token manager, responsible of xform metadata.
moar haxx