Vending reloaded!

This modification adds vending machine restocking units. They can be ordered from cargo and used on a vending machine (once the service panel has been unscrewed) to restock the machine with items.

At the moment I only made restocking units for the booze-O-mat, the hot drinks machine, the Snacks and Soda machines and the cigarette machines. I'm planning to make more later.

Each restocking unit is currently set to refill about 1/3rd of the machine's capacity. Restocking units have charges that get consumed as they restock products. The restocking will split charges equally between the different products.

This mod consider that the initial content of a machine is the maximum it can contain, and the restocking units will not be able to refill them past that (it will not consume charges for items it did not stock tho).

Also, vending machines will not dispense items if their service panel is unscrewed (service mode?)

Obviously, Restocking units will NOT restock coins or sindie items.

![image](https://f.cloud.github.com/assets/598409/1556158/e5f225ea-4eb1-11e3-8bdb-7df38eab5770.png)