* jc/mktree:
mktree: validate entry type in input
mktree --batch: build more than one tree object
mktree --missing: updated usage message and man page
mktree --missing: allow missing objects
t1010: add mktree test
mktree: do not barf on a submodule commit
builtin-mktree.c: use a helper function to handle one line of input
mktree: use parse-options
build-in git-mktree