Provide labels when a cycle is detected

[milesj]

Right now the cycle detection isn't very helpful since it doesn't tell you where the actual problem is.

It would be nice if it included a vector of the cycle path that triggered it, for example: SolventError::CycleDetected(vec!["foo", "bar", "baz", "foo"]).

[mikedilger]

I just pushed a commit that should do what you want. It passes internal tests, but I haven't used it myself (I haven't used solvent in years). Let me know if it works for you.

[milesj]

@mikedilger Not seeing any commit :P

[mikedilger]

Oops I pushed it to my private repo server. Check now.