Better integration of poly-org-mode with sub-modes

[vapniks]

With this code poly-org-mode sub-mode buffers can now find their respective process buffers so we can use commands such as ess-switch-to-inferior-or-script-buffer and ess-eval-region-or-line-and-step from within the org-mode buffer.

[vspinu]

Hi @vapniks,

Are you still interested in this? polymode has been rewritten recently and poly-org now lives in its own repo.

Regarding outline levels and regexp I think this makes sense for all modes not just org-mode. So I already included those in pm-move-vars-from-base.

Regarding the second part, it should go to poly-org and I would like to see a few minor changes. First is use &rest args in the argument. Second, use with-eval-after-load for the advices.

[vapniks]

Yes, when I get the time I will have another look at it.