Fix maps and check them better

[Jozzy]

Of course this server based on idea of NFS, but this is still MTA, and for new players its not obvious that you need just look at the minimap and not try to do shortcuts. At least you need to add visible barriers in maps mentioned by AleksCore. And yeah, dat invisible wall at Dockside Rush XD
With time you stop paying attention on this defects, but it's still ruining all impression of playing.