Re: Distinct for indices, is it good library Api?

[b3liever]

In the end, I think, it makes no sense to write an 1:1 port of petgraph, I will 
do a library that is usable at least by a noob (me). I think its best not to 
export `EdgeIndex` and keep edges private, if the weight must be updated, 
updateEdge is available, findEdge though will be private. Removing nodes and 
edges invalidates the last indices, so I won't implement it.