Fix #1424 (decon busy timing)

The RnD console now clears the deconstructive analyzer's "busy" flag after it finishing its work.
Now players can't stick things in it while it's deconstructing.
Fixes #1424 (deconstructive analyzer eating objects).

![deconbusy](https://cloud.githubusercontent.com/assets/6355724/4179286/95838364-36bf-11e4-8bc9-af095bc541f4.png)