Add a control pause button to scene editor

[grizeldi]

Add a button to scene editor that pauses/resumes all controls in the scene so that moving spatials don't run away.
See:
http://hub.jmonkeyengine.org/t/sdk-maintenance-plan/35259/30

[MeFisto94]

I have implemented them as SceneExplorer Context Menus now actually because:
a) There was no way to start/stop single Controls
b) To emphasize how Stop All works (it simply iterrates through all children and stops it's controls)

[dokthar]

@MeFisto94 what's the default behavior ? I think controls should by default enabled.

[MeFisto94]

They actually are.

[grizeldi]

That is exactly how I imagined it, thanks!

[MeFisto94]

Note: Due to problems, I'll push another commit soon.
It will only work for AbstractControls and Descendants. Not sure how it is with internal controls, but since you use that for own Controls most of the time it shouldn't be a problem then.