currently similar to HashMap, which is also based on that version. The kernel
has OpenHashTable by Hugo Santos, which is a bit nicer, but I didn't want to
change too much code, although HashMap and HashSet exist for this as well.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35077 a95241bf-73f2-0310-859d-f6bbb57e9c96
