Consistent cones

Antennas will now attempt to connect to all targets within their field of view, regardless of whether the antenna is pointed at a celestial body or at a vessel. The new cone logic works seamlessly across SoI boundaries (#14), and works consistently when targeted at Active Vessel.

I've also done some more maintenance on the network code. Most of this is changing and standardizing variable names, but in 7ceaf08 I also copied the ability of `RangeModelExtensions.IsTargetingActiveVessel()` to work correctly while in the tracking station to `NetworkManager.operator[]`. In the future the code in these two functions should be merged into a single function (`getActiveVessel()`), but I'm not sure where to put it.

Likewise, I'm not sure if `getPositionFromGuid()` really belongs in `RangeModelExtensions`, but I'm not sure where else to put it.