Add new funding acknowledgment to footer

[horsburgh]

Need to add the following grant number to the footer: 2012748

This material is based upon work supported by the National Science Foundation under Grants 1224638, 1332257, and 2012748.

The rest of the text of the footer can stay the same.

[aufdenkampe]

Did the NSF BiG CZ project fund any work or maintenance on this? It was the only funding we had for ODM2 for 2015 to late 2017. If so, let's also cite 1339834.