Too many (old) branches

[bennesp]

There are many branches in this repo
step-1 ... step-9 branches are ok

Then there are other branches named wiro, progettino and so on, maybe old

Then there are some named step0 ... step3 (note the missing dash)

It would be nice to clean the repo removing useless branches

Personally I had a problem while developing because I did a checkout to step3 branch, unintentionally (branch name without the dash), and was wondering what was wrong. After some time I realized it.