Merge branch 'tk/simple-autosetupmerge'

"git -c branch.autosetupmerge=simple branch $A $B" will set the $B as $A's upstream only when $A and $B shares the same name, and "git -c push.default=simple" on branch $A would push to update the branch $A at the remote $B came from. Also more places use the sole remote, if exists, before defaulting to 'origin'. * tk/simple-autosetupmerge: push: new config option "push.autoSetupRemote" supports "simple" push push: default to single remote even when not named origin branch: new autosetupmerge option 'simple' for matching branches