Allow customizing filename and description

Usually the java.io.File's name is good enough, but if you're using a
tempfile, more control over the filename is useful. And the
Content-Description header can also be helpful to have.
Document Colin's attachment file name addition.
Add Colin Jones.
Update copyright year.
v0.10.0.
Move clojure out of proper deps.
v0.10.1.
1.11-SNAPSHOT.