Accurate fuel values & basic DB backup bat file.

This pull request includes add the fuel capacity variable to the sea and air vehicles with accurate fuel capacity values for people to use in refueling scripts plus a basic db backup batch file, including a text file of instructions, for people with dedicated servers so they can easily backup their databases.

Sorry, not sure how to separate them in to two pull requests.

Fuel capacity: Issue #1277
DB backup: issue #1397