doi_classes: for doi relations the APA citation is downloaded from citation.doi.org and formatted in the landing page, precision of geolcoation is agumented to 3 digits, doi urls matching only return one result in the DOIRelationFactory, improved url html href formatting with a dedicated class method

added support for changing DATA_LOCATION through the filename, added support for setting an attribute to an empty string, improved default value for DATA_MODIFICATIONS

added support for date ranges (default is open time interval where the start is taken from the file attribute DATA_START_DATE)

the closed interval option is supported (for a time range that will non longer be updated)

improved handling of NDACC achknowledgements, descriptions, ... : all depends if NDACC is in the FILE_ASSOCIATION attribute

added the standard NDACC acknowledgment sentence, added support for NDACC metadata files with a new RelationsFactory mapping sites to the ndacc metadata url

added DataCiteAPI for publishing DOIs, fixed some bugs in the html pages, removed relatedItemType and awardURI  not supported in the API

removed the addition of the CF attribute units: GEOMSQAQC requires this to be equal to VAR_UNITS which breaks the CF compliance... For now choose to not write this attribute. It can be undone when QAQC accepts the CF values