Ctl+Tab/Cmd+Tab should switch bettween opened tabs on editor

[saint11]

The problem most likely lies in EditorScene.cs, there's something about ImGui that we are misunderstanding that's causing a weird behaviour when trying to cycle through tabs.

Basically we need it to cycle only the _selectedTab to the windows opened on _selectedAssets.

[MarcinKuder]

I've noticed that commenting out "ImGui.SetNextWindowFocus()" in EditorScene_Editors.cs (line 76) makes tab switching better. It's not perfect - at the end of cycle it switches focus to the main menu but it is still better than with the line present.
Not sure what are the side effects.

[saint11]

Got it working much better on b9dfdb4, not 100% though. I still can't figure out how to remove the main menu bar from the list.