ENH: Add Time support to Reader. We check for CollectionType attribute on the main top level grid, and if it is temporal, we collect the list of time values from each sub grid. This is exported. When Time values are requested we output the correct sub grid.
Lots of internal changes to tidy up the code and handle information.
BUG: Several bug fixes for reading in parallel. Extents were not always correct. Seem to be ok for image data now