Patch for to change data loaders to update values not override

[GoogleCodeExporter]

This patch contains the beginnings of enhancing the data loaders so that the 
only update values that have changed, and remove values that don't exist 
anymore. It is working the DwcCSVLoader but the DWCALoader has not been 
finished yet.

Once this is implemented in the biocache we can remove the delete-obsolete 
dr376 step for AVH as it will automatically remove the obsolete column values.

Original issue reported on code.google.com by natasha....@csiro.au on 2 May 2014 at 5:56

Attachments:

• Start_of_update_load_not_replace.patch