This functions more or less identically to using a media out value, but the
desired speed is preserved through block length changes, even if the block's
length is reduced to zero (i.e. no rounding errors).
Splitting commands would run CopyInputs after set_length. Since length is now
a parameter (aka a NodeInput) the former would override the latter breaking the
implementation. This commit fixes that.
An earlier commit implementing media in and out parameters was primarily for
this addition. A simple control dialog for the clip's speed presentation
reimplemented from the old codebase.
Fixes recurring design issue that the Blocks were a frequent exception to the
DAG concept. The Blocks connecting to each others inputs/outputs while not
necessarily being "dependent" on each other to produce an image continually
causes issues while trying to create a rendering code path. This redesign
should provide a more "directed" approach to the directed acyclic graph.
itsmattkc