"git cat" and "git ls"

Hello,

        following the "git diff" wrapper I've done two new wrappers:

git cat: USAGE='<tag|commit|blob> | [<ent>|-1|-2|-3] -- <file>'

    It shows the content of the giventag/commit/blob.

    You can also ask for a file in a tree or in the index (stage
    optional).

git ls: USAGE='[<ent>] [--] <path>'

    It lists the files in <path> in the <ent> or in the index.

  Santi