add a quick return path in LuaSystemPath:SystemOnly and :SectorOnly
fix -Wmaybe-uninitialized warning when reading hyperclass_cap
fix -Wmaybe-uninitialized warning in LuaTable::GetMap<std::string,int>
sanity check in SystemPath::IsSameSystem that both paths point to systems
clean up confusing tests in l_sbodypath_attr_{system,body}_index
add extra error checking in Lua SystemPath methods
Merge pull request #3086 from johnbartholomew/cleanup

General cleanup