Radar signals

Adds a new entity called "Radarsignal combinator" When placed next to a radar it will output the amount of entities found in the visible area as a signal It is unlocked with the "Advanced Radarsystems" technology

The idea was to have some sort of indication when enemy bases are near an outpost to then call the artillery train to show up

How it works

1. Place radar
2. Place new radar-signals combinator next to the radar
3. Set desired entities to scan for inside the combinator
4. Connect to circuit network
5. Every 4th second it will output the amount of found entities based on given filters in the visible scanned area