MAJOR change.
Split DataDistribution into 2 classes: DataDistributer and DataDistribution.
I haven't actually changed or added functionality
DataDistributer deals with the distribution of the data, while DataDistribution deals with things to do when data is already distributed, right now is only a few data checks
Note that DataDistributer now has two db fields: srcDb and destDb. This is different to before, when destDb was rather a parameter passed as arguments to the methods
Methods in DataDistributer have been tidied up a little (specially load and dump ones)