BatchCraft

Adds feature of batch crafting into crafting menu.

1) open craft menu and select recipe
![bcraft01](https://cloud.githubusercontent.com/assets/6969268/4140508/de8441e2-33a5-11e4-9ac6-80a71ca9cc8e.PNG)

2) press [b]atch to generate batch screen for selected recipe
![bcraft02](https://cloud.githubusercontent.com/assets/6969268/4140520/fb52feb2-33a5-11e4-961c-078f78b48737.PNG)

3) either select one of batch recipes, or return to previous screen by pressing [b]atch again


Looks like this was broken before, but this doesn't fix it.  What you want is something like:
```
for( iter = conts.begin(); iter != conts.end() ) {
    if( iter->is_container_empty ) {
        // Do stuff
        iter = conts.erase( iter );
} else {
    iter++;
}
```