Blender Git Loki

Sequencer fix: Transform Strip wouldn't work with default_fader
* added default_fader to transform strip, since it used the old fac too.
* removed ANIMATEABLE attribute from the settings in the transform strip, since they are animated via the effect_fader and not directly for now. (too confusing)
* UI: only show default_fader for the effect strips that support it

Sequencer Durian feature: uniform scale for Sequence transform strip.
* for now re-using variable for x-axis scaling.

Note: This brings back functionality as close to 2.49 as possible. The Start and End values in the current design are not meant to be animated directly, but via the effect_fader.