Add --replace option to set.

Only try to replace old license with the new one if it is asked for
by specifying the "--replace" option.
Merge branch 'tgulacsi-master'
Adds godeps
Added Gitter badge
Merge pull request #10 from gitter-badger/gitter-badge

Add a Gitter chat badge to README.md
Golint fix
Merge branch 'master' of https://github.com/c4milo/licentia
Move <files> params to the last.

This enables the caller to use shell globbing,
either specify *.go, either '*.go', or the combination of them.