Chef PDA cartridge and bugfixes

* Added: New PDA cartridge for the chef equipped with a reagent scanner ![cart_chef](https://cloud.githubusercontent.com/assets/4912533/2836830/688231ae-d007-11e3-87eb-a675e3e329fc.png)

* Bugfix: Snackbars are now deleted when a reaction causes their reagents to be completely emptied
* Bugfix: Fixed CondiMaster displaying a pill bottle message due to some inheritance from the ChemMaster