Merge branch 'ls/subtree'

"git subtree" updates. * ls/subtree: (30 commits) subtree: be stricter about validating flags subtree: push: allow specifying a local rev other than HEAD subtree: allow 'split' flags to be passed to 'push' subtree: allow --squash to be used with --rejoin subtree: give the docs a once-over subtree: have $indent actually affect indentation subtree: don't let debug and progress output clash subtree: add comments and sanity checks subtree: remove duplicate check subtree: parse revs in individual cmd_ functions subtree: use "^{commit}" instead of "^0" subtree: don't fuss with PATH subtree: use "$*" instead of "$@" as appropriate subtree: use more explicit variable names for cmdline args subtree: use git-sh-setup's `say` subtree: use `git merge-base --is-ancestor` subtree: drop support for git < 1.7 subtree: more consistent error propagation subtree: don't have loose code outside of a function subtree: t7900: add porcelain tests for 'pull' and 'push' ...