Container for class metacommunity.
# S4 method for metacommunity
show(object)object of class metacommunity
type_abundancetwo-dimensional matrix of mode numeric
with rows as types, columns as subcommunities, and elements containing  
relative abundances of types in subcommunities.  In the phylogenetic case, 
this corresponds to the proportional abundance of historic species, which
is calculated from the proportional abundance of present day species.
similaritytwo-dimensional matrix of mode numeric with 
rows as types, columns as types, and elements containing pairwise 
similarities between types
ordinarinesstwo-dimensional matrix of mode numeric 
with rows as types, columns as subcommunities, and elements containing the
ordinariness of types within subcommunities
subcommunity_weightsvector of mode numeric; contains
subcommunity weights
type_weightstwo-dimensional matrix of mode numeric, 
with rows as types, columns as subcommunities, and elements containing 
weights of types within a subcommunity
raw_abundance[Phylogenetic] two-dimensional matrix of mode 
numeric with rows as types, columns as subcommunities, and elements 
containing the relative abundance of present day species
raw_structure[Phylogenetic] two-dimensional matrix of mode 
numeric with rows as historical species, columns as present day 
species, and elements containing historical species lengths within lineages
parameters[Phylogenetic] tibble containing parameters 
associated with each historic species in the phylogeny