Big tool rename.

As promised, this is the "big tool rename" patch.  The primary differences
since 0.99.6 are:

  (1) git-*-script are no more.  The commands installed do not
      have any such suffix so users do not have to remember if
      something is implemented as a shell script or not.

  (2) Many command names with 'cache' in them are renamed with
      'index' if that is what they mean.

There are backward compatibility symblic links so that you and
Porcelains can keep using the old names, but the backward
compatibility support  is expected to be removed in the near
future.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/howto/revert-branch-rebase.txt

@@ -182,10 +182,10 @@ And the final repository status looks like this:
 ------------------------------------------------
 $ git show-branch --more=1 master pu rc
 ! [master] Revert "Replace zero-length array decls with []."
- ! [pu] git-repack-script: Add option to repack all objects.
+ ! [pu] git-repack: Add option to repack all objects.
   * [rc] Merge refs/heads/master from .
 ---
- +  [pu] git-repack-script: Add option to repack all objects.
+ +  [pu] git-repack: Add option to repack all objects.
  +  [pu~1] More documentation updates.
  +  [pu~2] Show commits in topo order and name all commits.
  +  [pu~3] mailinfo and applymbox updates