Yggdrasil 0.1-019

Updated core library to 0.5.9, presenting these changes: Changed The routing algorithm has been updated with RTT-aware link costing, which should prefer lower latency links over higher latency links where possible The calculated cost is an average of the link RTT, but newly established links are costed higher to begin with, such that unstable peerings can be avoided Link costs are only used where multiple next-hops are available and will be ignored if there is only one loop-free path to the des