Creates the test network by creating trees and storing them in the hash table using test functions in CTMain, running the consensus tree and network creating algorithms and then outputting the network in a window.
The file name (without path) that is chosen to be the base name for all output files,
plugins will define their own output file names by adding extensions to this base name.
Calculates the total log-likelihood of the state by adding the log-likelihood factor
contributions from all model extension plugins to the log-likelihood of the tree.