Remove CONSTRUCT_ONLY flag from 'base-stream' property of GFilterInputStream and GFilterOutputStream
Submitted by Eduardo Lima Mitev
Link to original bug (#616869)
Description
Having this property only available at construction time limits the ability to build streaming pipelines dynamically of modify them on-the-fly.
Proposal is to make the property fully readable/writable and move the 'base_stream' protected object into private structure. This change would also require to add a 'g_filter_(input/output)_stream_set_base_stream' method.