Use node-uuid as default random path generator

[Starefossen]

PR #41, and v1.1.0, introduced the possibility to use a custom random path generator such as node-uuid. The benefit with Universally unique identifiers are that they are guaranteed to be unique and we no longer need the collision check which will speed things up a little 😄

This is a breaking change, so this will have to wait for v2.0.0 before we can do the switch.