Merge branch 'jc/ll-merge-binary-ours'

"git merge -Xtheirs" did not help content-level merge of binary files; it should just take their version. Also "*.jpg binary" in the attributes did not imply they should use the binary ll-merge driver. * jc/ll-merge-binary-ours: ll-merge: warn about inability to merge binary files only when we can't attr: "binary" attribute should choose built-in "binary" merge driver merge: teach -Xours/-Xtheirs to binary ll-merge driver