[Changeset] new bzip2 function

[John W. Eaton]

On 26-Oct-2008, Thorsten Meyer wrote:

| the applied changeset contains a bzip2 function which is analog to the
| gzip function.
| While fixing the @seealso references to prepare for
| @seealso->@ref expansion I found a reference to (the up to now missing)
| bzip2 in the docstring of bunzip2.m, so I added this function (instead
| of removing the reference to it in the helpfile).

Given that this function is almost identical to the gzip function,
it seems it would be better to abstract the common parts into a
separate function, then write the gzip and bzip2 functions in terms of
the common function.

jwe