Update to new Go subrepository import paths.

c.f. https://groups.google.com/d/msg/golang-nuts/eD8dh3T9yyA/l5Ail-xfMiAJ
Flag names of type time.Duration that have unit suffixes.

This catches people writing code such as
	var timeoutSecs = 5 * time.Second
Update stale links to reflect wiki move to GitHub.

Signed-off-by: David Symonds <dsymonds@golang.org>