impl Display rather than print()

[bastien vigneron]

Is there any particular reason for using a biscuit.print() rather than implementing the Display trait ?

[Geoffroy Couprie]

there was no real reason, implementing Display would make sense, that should be an easy PR

[bastien vigneron]

See #117

[Geoffroy Couprie]

closing this now than #117 is merged, thanks!