Struct members loc/size were misleading as they read as if the object
data stored object level transform channels. Rename these to match RNA
with a `texspace_*` prefix to make it clear these struct members only
apply to texture-space transform.
Also rename ME_AUTOSPACE & ME_AUTOSPACE_EVALUATED to
ME_TEXSPACE_FLAG_AUTO & ME_TEXSPACE_FLAG_AUTO_EVALUATED.
9e5e2aa775