Make weapondef docs reflect Lua types

[sprunk]

1. defaults for booleans should say true and false, not 1 and 0:
   
2. std::string should say just string, there is no std:: in Lua.
   
3. float should say "number". IDK about int and unsigned int, technically they're not lua types either but they convey "no fractional values" nicely.
4. float4 is sometimes (always?) actually float3, and is not a Lua type. Should probably say "{number, number, number}"
   
5. not directly related to types, but the "scaling" is often not too helpful. Input should just be in natural units, but I guess that is already covered by #801.