Make the dag example show genericity

[efugier]

To be truly usable in a wide range of situation, it needs to be generic, show the world that it is !

[declanvk]

So would you suggest showing multiple examples that all use different data? Or using the data structure in a generic setting, for example in some algorithm like shortest path?

[declanvk]

Also, I had some thoughts about making the container not hold any data (thus removing the generic parameter), but actually returning symbolic keys that would represent the nodes in the graph.

This would decrease the complexity of the data structure, and entirely remove the need for the bimap module. If you have any thoughts on that, please let me know.

[efugier]

I think the more example there is the better :)

Dag are often use in settings with high performances requirements, I suggest doing whatever is best for performances !