0.07 (08/15/2004)
    (ms) doc and test fixes for new rrdtool release 1.0.49. dump()
         and restore() are now supported.

0.06 (06/21/2004)
    (ms) added 'start' param in create() docs
    (ms) JJ Knitis <jj@dangercreative.com> provided a fix for
         multiple 'color' settings in graph. Added new graph/color
         syntax.

0.05 (05/26/2004)
    (ms) added support for dump() and restore(). Test cases in
         t/007Dump.t will wait until these functions are 
         available in rrdtool, and are skipped until then.
    (ms) Some graph options don't have parameters, they can
         specified via option_name => undef now.
    (ms) Added lower_limit graph option
    (ms) Added eg/graph.pl as a graph example

0.04 05/22/2004
    (ms) added more functionality to graph(), new test cases.
    (ms) if a graph contains several files, use the defaults
         from each file
    (ms) added tune(), info(), last().
         dump()/restore() added also, but not activated yet, 
         because not available via RRDs.

0.03 05/18/2004
    (ms) fixed discovery of CFs
    (ms) fixed update with values/hash and added test case

0.02 05/16/2004
    (ms) used rrdtool info for meta queries

0.01 05/12/2004
    (ms) Where it all began.

TODO:

* Why doesn't RRDs offer dump()/restore() methods?
* some less frequently used graph parameters like CDEF, PRINT, x-grid
  aren't integrated yet or could be integrated more OO-like.
* fetch_start/next iterator with saved timestamp, without caching all values