added a debug warning and a couple of lines so that the script
returns to the current working directory when it finishes
modified so that a separate methylation data file (eg from Synapse)
can be used rather than obtained/parse from the dcc-snapshot (which
is the default mode of operation)
modified so that the output file name will include part of the feature
name rather than just the class label, when the class label is not
very distinctive (eg YES/NO or 1/0 etc)