dispweights work without 'group' argument
add dispweight3: overdispersion wrt any glm model

Clarke's dispweight is based on the hypothesis that count data should
follow Poisson distribution, and species overdispersed to the Poisson should
be downweighted. The basic model assesses the expected values of species
and their overdispersion wrt to class means for a single factor and then
estimates the significance of the overdispersion using individual-based
simulation within these same classes. Function dispweight3 generalizes this
by allowing a formula that specifies any fitted model, but estimates the
significance of the overdispersion analytically from Pearson residuals.
typo
all dispweights return transformed data (with attributes)