SCOAP3: Adding arXiv id for Elsevier

* Adds arXiv id to record from Elsevier papers.
SCOAP3: New test suit with empty methods (TODO).
SCOAP3: Temporarily disables references extraction
SCOAP3: removing MathML namespace:

* Adds functionality to xml_to_text function that allows to remove
  MathML namespace from tags.
SCOAP3: mathml cleanup fix

* Fixes removal of "mml" namespace prefix from tags - removes postfix
  from xmlns definition.
SCOAP3: Empty test methods for MathML
SCOAP3: class for harvesting contrast-out scheme

* Creates a class that allows to connect to a server and do some
  magic.
SCOAP3: tmp
SCAOP3: Downloadind tar files
SCOAP3: gets all correct xml and pdf URL from CONTRAST-out protocol.

* Adds reading .ready files from FTP server.
* Adds downloading tar packages from server.
* Adds checking MD5 of tar packages.
* Adds extracting packages to TMP directory.
* Adds getting xml and pdf URLs from dataset files.
SCOAP3: harvesting Elsevier

* Adds harvesting Elsevier FTP server.
SCOAP3: Downloads ".ready" files

* Changes reading ".ready" files to downloading them and reading
  later.
first super small logging
SCOAP3: Logging to file  for contrasct_out.py.
SCOAP3: Logging added for scoap3utils.py.

* Adds generating log file for every Elsevier harvest or package
  given. Logs connection to server, downloaded packages,
  retrieved ".ready" files, getting journal and issue metadata,
  creating records for bibupload.
SCOAP3: MD5 error registration.

* Adds using registr_exception for MD5Error.
* Adds missing contrast_out_utils file.
SCOAP3: New place for storing packages from Elsevier.

* Changes directory for storing Elsevier packages.
SCOAP3: Multiple afiliations support.

* Adds support for multiple author affiliations.
SCOAP3: Adds Springer parsing.

* Moves code to different files.
* Adds 1st step for Springer packages parsing - extracting package
  to new location in var/data folder, normalizing packages,
  finding articles.
* Fixes some stuff in Elsevier packages (don't remember what was
  that;p)
* Adds DTD file for Springer.
tmp