Implement a lock feature

[andrew0]

CSSprite already supports it, we just need to set it up in the sprite info panel. It will lock a sprite so it can't accidentally be dragged, resized, etc.

[psineur]

@andrew0, i'm moving this issue to 0.2, cause its not that we can't live without in 0.1 But if you d like - solve it anytime for 0.1

I'm just trying consider & choose minimal amount of features/issues to release 0.1 as soon as possible even by myself.