Does not work with Blender 2.92 alpha

In Blender 2.92 alpha the patch D8393 is incorporated. The attributes use_crop and use_translation are no longer used and throw an error. The use of a transformation strip is also no longer necessary for standard scale, crop, rotate and translate opertions.

[tin2tin]

#20

[marcgardent]

@zeograd implemented the fix and now the addon uses strip's transform.

https://github.com/zeograd/VSE_Transform_Tools