[Tracker] Review trackerd command line options

[Luca Ferretti <elle uca libero it>]

As previously mentioned, the i18n support in trackerd should only
applied to --help messages.

Needed changes are yet in my cvs sandbox, but scrolling the trackerd.c
source I think that we should rename flags as follow:

        ## PROPOSED             ## CURRENT
        --exclude-dir -e        --ignore-dirs
        --include-dir -i
        --no-index              --disable-indexing
        --debug                 --enable-debug
        --turbo -t              <same>
        --low-memory -m         <same>
        --language -l           <same>

## Notes ##

      * The --include-dir will replace the G_OPTION_REMAINING, matching
        the --exclude-dir in feature and "layout"
      * the *dirs in current --ignore-dirs is wrong, 'cause you can
        specify one directory for each --ignore-dirs option (this is how
        G_OPTION_ARG_STRING_ARRAY works). To specify multiple
        directories, you have to set multiple options, so the plural
        form is wrong.
      * GOption seems to support a specific array for filenames,
        G_OPTION_ARG_FILENAME_ARRAY. I don't know what's the difference,
        but we are parsing filenames, so maybe we should it instad
        G_OPTION_ARG_STRING_ARRAY

Of course this could break current installations of tracker, if you are
launching this with custom flags. :-(

Comments ?

## Cool Additions ##

        --replace       As in beagled, could be used to shutdown and restart
        the daemon (is it needed?)
        
        --shutdown      Just to shutdown the daemon :-)