Added clarification to license that generated code is owned by the owner of the
input file.

diff --git a/COPYING.txt b/COPYING.txt
index 1941a11..705db57 100644
--- a/COPYING.txt
+++ b/COPYING.txt
@@ -26,3 +26,8 @@
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Code generated by the Protocol Buffer compiler is owned by the owner
+of the input file used when generating it.  This code is not
+standalone and requires a support library to be linked with it.  This
+support library is itself covered by the above license.