Small fixes

* Stops players from leaving webs/slime on roads while in vehicles
* Updates FAQ in the '?' menu
* Makes vitamins have an effect/message again (must have been accidentally deleted at some point) - Fixes issue #1136
* Vehicles with multiple gasoline tanks drain properly - Fixes issue #1084
* Fixed old mutation effect removal when upgrading mutations - Fixes the stat gain portion of issue #1259
* Fixed hacksaw name (should be "hacksaw" not "hack saw" according to wikipedia).

Also added a slight pain effect to Acid Drizzle weather (1 in 20 chance of adding 1 pain, up to 10). Rain coats now offer protection against acid drizzle effect and small protection against acid rain effect (since the message was already there). This fixes issue #1161.