Set ship research onlyWorksIfTierLabsExist to False

[eljeffeg]

The ships (at least the Humans) have the onlyWorksIfTierLabsExist set to True, with exception of the Titan. If the ship is researched, it makes sense that you'd still be able to build it if you lost labs, so we should probably make it False.

[eljeffeg]

We expect this might be done to prevent people from building up research and then destroying the facilities to replace them with other structures. If you only need the facility for as long as you're researching, you could destroy it afterward. It may be a way of forcing the player to maintain the facilities if they want to build the ships. Therefore, we're going to keep it as is.