Update menu_tags.py

Parent is nulled for menu nodes, this isn't very comfortable in some situations
fixes #2417
Merge pull request #2634 from digi604/fix-2417

fixes #2417 (publish in language that is not in CMS_LANGUAGE)
Merge pull request #2635 from FinalAngel/develop

modal size issues
bumps version to 3.0b4.dev7
Update menu.py
setup select2
fix drag&drop
Merge pull request #2637 from digi604/fix-dd

fix drag&drop
Merge pull request #2632 from belegnar/patch-1

Update menu_tags.py
Merge pull request #2636 from belegnar/patch-2

Update menu.py
Merge pull request #2638 from FinalAngel/develop

Fixes issues with the sidebar
cleanup
cleanup
remove placeholder form fields
Fix copy plugins from language from the placeholder menu.
Added some padding to the body to make the placeholder menu visible so that the test works.
Added 2 frontend tests for checking if the clipboard copy and the copy from language item work.
Merge pull request #2640 from digi604/fix-link

Fix link
fixes #1234