plotRegulatoryGraph: This function layouts a regulatory graph and plots it using Rgraphviz.
Description
This function takes a regulatory graph as generated by
pathway2regulatoryGraph and plots it using standard layout
options of layoutRegulatoryGraph. This function is a
wrapper for layoutRegulatoryGraph with standard parameters.
Subgraphs can be painted with different colors. This can be
done by passing parameter subgraph a list of character
vectors with node names.