Places an element at a specific index of an array:
```
_array = [1,2,4];
_index = 0;
_value = 0;
_array insert [_index, _value]; //[0,1,2,4];
_index = 3;
_value = 3;
_array insert [_index, _value]; //[0,1,2,3,4]
_array insert [6, "outOfBound"]; //[0,1,2,3,4,nil,"outOfBound"]
```
or maybe it could work like `append`:
```
_array = [];
_index = 0;
_values = [1,2,3];
_array insert [_index, _values];//[1,2,3];
```
alternative name: `insertAt`
maybe the command could support strings too?