Descriptive names for edit_distance

[boeddeker]

Hello, what do you think about using descriptive names for the arguments of edit_distance? With descriptive I mean something like reference and hypothesis. In the "plain" edit_distance you only count the numbers of errors, and you can switch the arguments. It changes, once you report ins/del/sub.

While a change of the code arguments would be a breaking change, it would be nice to have it at least in the README and the docsting. I want to use kaldialign to report ins/del/sub, but now I have to think about, which argument is which.