Megaton caverns nuclear lab and playable fire hydrant

Adds a hatch in the megaton bomb (I know - I\'ll explain it) that leads to a massive cavern where nuclear bombs have been under development. Also, adds a wieldable fire hydrant. My idea for explaining the hatch is that the Megaton bomb was intentionally aimed at a nuclear bomb development centre, in order to cause a chain reaction. The cavern itself is massive and is intended to look like a devastated nuclear lab. At the end of the cavern is a mini-nuke lab which has the Fat-man, MIRV and many mini-nukes. Also in this area is the firelance, alien blaster and plenty of ammo for both. This means that it is also useful if you ever want to quickly get your hands on some serious firepower. Another feature of the mod is that the cavern also contains 3 powerful melee weapons - 1 of which is the newly playable fire hydrant, as wielded by Behemoths! This mod is nowhere near perfect, just thought people might like a massive playground, I use it to test mini-nukes indoors. Images hopefully in the next day - apologies! Ideas for improvement: - re-size hydrant - add icon in PIP-boy 3000 for Hydrant - improve walkway in lab - adjust hatch (slightly awkward position) - quest/further inclusion in lore - general development