Allow field formatting in dataflows

Right now there doesn't seem to be a way to set field level properties at a Dataflow level. Specifically, DataType, Formatting, Summation, Data Category and Sort by column. This has to be applied each time you import a dataflow into a dataset. This is particularly obvious when using a Date Dimension which are often imported to datasets multiple times per date, and you have to change all the sort orders on alpha months, stop it summing years and months, and change formats to short date to remove time. This should be all set at the dataflow level allowing overrides at the dataset level.