Fixes bits leaved during name change.
Signed-off-by: NAlexey Nezhdanov <snake@penza-gsm.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This means that you can take a tag object, and do

	git-cat-file commit tagname

and it will cat the commit that the tag points to. Or you can
cat the tree that a commit (or tag) points to.

It still gives the old behaviour if you just give it the
original type, ie if you want to see the tag object itself,
you'd do

	git-cat-file -t tagname

and you'd get the expected tag output.

This allows the programs to use various simplified versions of
the SHA1 names, eg just say "HEAD" for the SHA1 pointed to by
the .git/HEAD file etc.

For example, this commit has been done with

	git-commit-tree $(git-write-tree) -p HEAD

instead of the traditional "$(cat .git/HEAD)" syntax.

Now there is error() for "library" errors and die() for fatal "application"
errors. usage() is now used strictly only for usage errors.
Signed-off-by: NPetr Baudis <pasky@ucw.cz>

And fix up the warnings that it pointed out. Let's keep the tree
clean from early on.

Not that the code is very beautiful anyway ;)

New syntax: "cat-file -t <sha1>" shows the tag, while "cat-file <tag> <sha1>"
outputs the file contents after checking that the supplied tag matches.

The tool interface sucks (especially "committing" information, which is just
me doing everything by hand from the command line), but I think this is in
theory actually a viable way of describing the world. So copyright it.