Create ChannelWorm DataSource / DataTranslator types

[mwatts15]

ChannelWorm produces data which should be stored in an owmeta bundle. To achieve this, a DataSource subclass should be created which describes records derived from ChannelWorm. A corresponding DataTranslator should be created which translates from the DataSource into a DataWithEvidenceDataSource containing Channel objects together with evidence supporting them (i.e., the documents from which the channel model is derived). For ChannelModel types as well, there is also an experiment type which describes how the model parameters are derived, or, alternatively, the homologous channel from which the ChannelModel properties are inferred.