[PATCH] ls-tree enhancements

[PATCH] ls-tree enhancements

This adds '-r' (recursive) option and '-z' (NUL terminated)
option to ls-tree.  I need it so that the merge-trees (formerly
known as git-merge.perl) script does not need to create any
temporary dircache while merging.  It used to use show-files on
a temporary dircache to get the list of files in the ancestor
tree, and also used the dircache to store the result of its
automerge.  I probably still need it for the latter reason, but
with this patch not for the former reason anymore.

It is relative to bb95843a5a0f397270819462812735ee29796fb4

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>