darcs-meld : use 'meld' to show patches and diffs for darcs repos
usage:
    darcs-meld [options]

examples:
    darcs-meld
        -> show unrecorded changes
    darcs-meld --patch PATCH
        -> show changes of patch PATCH
    darcs-meld --from-patch FROM-PATCH --to-patch TO-PATCH
        -> show changes from 'FROM-PATCH' to 'TO-PATCH'
Handling of options:
    All options of darcs-meld are given to the 'darcs diff' command
    so you can use all valid darcs options.
Patch specifications:
    'PATCH', 'FROM-PATCH' and 'TO-PATCH' are *patch specifications*
    They ary usually the first line of the patch comment without
    the leading '  * ' and enclosed in single quotes.
    See 'darcs help diff' for a comprehensive list of options.
Special characters in patch specifications:
    Since a *patch specification* is a *regular expression*,
    all characters that have special meanings in regular expressions
    should be preceeded by a backslash '\' if they are to be
    interpreted literally. This is for example the case for
    these characters:   *()[]
    See 'darcs help patterns' for details.