Editor continuously updating with Camera2D in scene

[neikeq]

Operating system or device:
Ubuntu 15.10 x64

Issue description (what happened, and what was expected):
The editor is continuously being updated/redrawn if the scene contains a Camera2D. I am not sure, but this issue may be a regression from #4373

Steps to reproduce:

• Add Camera2D to a scene
• Close the scene and reopen it
• The editor will be updating/redrawing continuously (check the progress wheel in the top right corner) like when Update Always is enabled

[neikeq]

Ping @bojidar-bg :)

[bojidar-bg]

Umm... yes? 😄

(I'll check asap)