cannot access `BlendMode` but PsdLayer.blend_mode() returns `BlendMode`.

[namse]

I'd like to use BlendMode but it doesn't exposed to user. would you make it public?

[wareya]

Reiterating that this isn't public. Without being able to access this type, this library is almost useless; you cannot even begin to attempt to properly render nontrivial PSDs.

[namse]

We have forked and modified this project for our use. We understand well how difficult it is to continuously maintain an open-source project. However, that doesn’t mean we don’t feel any regrets.

[chinedufn]

I would accept a PR that makes the BlendMode public.