LOCATE requires SCREEN 0

`SCREEN 0` enables terminal features for the command `LOCATE`.

This `LOCATE` will NOT work:

```
20 locate 10,10: ? "test"
30 ?:while i$="":?"hit ENTER to exit":i$=input$(1):?i$:wend
```

This `LOCATE` will work:

```
10 screen 0
20 locate 10,10: ? "test"
30 ?:while i$="":?"hit ENTER to exit":i$=input$(1):?i$:wend
```
