Taxicabs AI pack by Egon v1.5

Changelog
- Overall spawn system changed - taxis now spawn only in cities. No more taxicabs on highways or country roads (although they CAN leave the city and for example drive behind you anyway). 

- Added new taxicab for UK, and it's the first car in the pack NOT base on SCS vehicle - iconic LEVC TX! It spawns mainly in London, but you can meet it occasionally also in other UK cities. Model is very lowpoly, I did what I could with the textures and such, but it definitely adds atmosphere to British cities. Right now no more taxis are planned as I am fully concentrating on developing my own AI pack.