Extract all affiliations for each author

[ZhangWoW123]

Fix the issue where the medline_parser.parse_author_affiliation function will only extract the first affiliation. Now the function will extract all the affiliation for each author and use pipe | to concatenate them.

For example, if the XML file is

<Author ValidYN="Y">
  <LastName>Horvath</LastName>
  <ForeName>Hacsi</ForeName>
  <Initials>H</Initials>
  <AffiliationInfo>
    <Affiliation>My 1st affiliation</Affiliation>
  </AffiliationInfo>
  <AffiliationInfo>
    <Affiliation>My 2nd affiliation</Affiliation>
  </AffiliationInfo>
  <AffiliationInfo>
    <Affiliation>My 3rd affiliation</Affiliation>
  </AffiliationInfo>
</Author>

Then the affiliation for this author will be

My 1st affiliation|My 2nd affiliation|My 3rd affiliation