Improves shuttle autocall() [Fixes #1422]

Aran missed out some important checks:

- The Code now checks for a POWERED Comms console
- The Code now checks for a NOT BROKEN Comms console
- The Code no longer loops pointlessly if the gamemode bans shuttle calls anyways
- The Code now returns after the gamemode check (this is just formatting, no real change)

Fixes #1422