DOC: Replaced all BSD style licenses with "BSD 3 clause"

Replaced all BSD style licenses with "BSD 3 clause"
Not checked yet!

Removed duplicate "3 clause, 3 clause"

Removed trailing period if exists

Fixed some missed licences, still about 50 to do, but those can be automated

Think I got the last of them.

Apparently me and sed have different ideas of regex.

Found a few more