Blender Git Loki

Fix byte-to-float conversion when using scene strips in sequencer with identical color spaces

Fix T50882: VSE: Blend Modes on Scenes do not layer properly
Fix T51002: Scene strip with Alpha over not working as expected

The byte-to-float conversion was being skipped if the color spaces of the sequence and the scene
are the same, which is the default, resulting in any non-float strips becoming invisible.

Reviewers: sergey

Differential Revision: https://developer.blender.org/D2635