piping and bug fix for when files are not UTF-8

Did I mess up the way targets works on line 89 of license_header ?

I put this in to handle a required list of files...

$ git log --pretty="%H %cn" | egrep -i "(colvar|klein|rogers|phuong)" | cut -d' ' -f1 | while read commit_hash; do git show --oneline --name-only $commit_hash | tail -n+2; done | sort | uniq | license_header -a --header-file=HEADER