HDF5 updates

[hollandjg]

• Make HDF5 saver use a struct for data input instead (allows overloading)
• Try including the full truecolor and falsecolor images in the HDF5 files – how much bigger are they? #992
• Also add date, satellite, bounding box, and information about the data product we use. (Might that be enough?)
• Later we could point to the specific granules, which are all guaranteed to be the originals.
• As long as we have the information for running the loader tool, the results are reproducible.