OAIHarvest: sample OAI-ArXiv conversion update

* DOI field added in 0247_2/a instead of 773__a.
  Create one field per DOI (addresses #678)

* Avoids creating whitespaces at beginning/end of collaboration
  field when 'keyname' or 'forename' or 'affiliation' tags are
  empty.

* Avoids creating whitespaces/newlines at the beginning
  of CERN PH report numbers.

* Correctly identifies CERN PH report number (for 084__a).

* Uses record creation date for 269__c, not "datestamp".

* New 595__a CERN-specific fields for PH-TH papers.

Signed-off-by: Jerome Caffaro <jerome.caffaro@cern.ch>