Added DCO.

Signed-off-by: Norv <norv@simplemachines.org>

DCO.txt

@@ -0,0 +1,25 @@
+Developer's Certificate of Origin 1.1
+
+      By making a contribution to this project, I certify that:
+
+      (a) The contribution was created in whole or in part by me and I
+          have the right to submit it under the open source license
+          indicated in the file; or
+
+      (b) The contribution is based upon previous work that, to the best
+          of my knowledge, is covered under an appropriate open source
+          license and I have the right under that license to submit that
+          work with modifications, whether created in whole or in part
+          by me, under the same open source license (unless I am
+          permitted to submit under a different license), as indicated
+          in the file; or
+
+      (c) The contribution was provided directly to me by some other
+          person who certified (a), (b) or (c) and I have not modified
+          it.
+
+      (d) I understand and agree that this project and the contribution
+          are public and that a record of the contribution (including all
+          personal information I submit with it, including my sign-off) is
+          maintained indefinitely and may be redistributed consistent with
+          this project or the open source license(s) involved.