C+A: add Matthew Cottingham (Individual CLA)

Done by addca, but codereview failed with a Python stacktrace,
so submitting by hand.

R=golang-dev
CC=golang-dev
https://codereview.appspot.com/16650043
database/sql: link to wiki in package docs

Update issue 5886

R=golang-dev, kamil.kisiel, adg, r, rsc, dave, arnehormann, bradfitz
CC=golang-dev
https://codereview.appspot.com/14087043

Committer: Brad Fitzpatrick <bradfitz@golang.org>