Added hasResearched function.

Adds a hasResearched function. Makes it possible to enable recipes requiring certain Thaumcraft research to be completed first.

For example:

```
import mods.thaumcraft.Research;

val stick = <minecraft:stick>;

recipes.addShaped(stick, [[stick, stick, stick]], function(output, inputs, craftingInfo) {
	if (Research.hasResearched(craftingInfo.player, "RESEARCHER1"))
		return output;
	
	return null;
});
```