add plos article type to extended feed

[russ]

related to #1125

add plos article type to the extended feed so that we can determine article type groupings in the issue feed.

[russ]

it looks like we're currently displaying both the mulgara article type, and the translation of that article type using config - can we only show the "human readable" article type (i.e. "Research Article")

 http://ploscompbiol-demo.plos.org/article/feed?type=Issue&extended=true

    <plos:article-type xmlns:plos="http://www.plos.org/atom/ns#plos">Research Article</plos:article-type>
    <plos:article-type xmlns:plos="http://www.plos.org/atom/ns#plos">//rdf.plos.org/RDF/articleType/research-article</plos:article-type>

thanks!

[rcave]

Moving to 0.9.3

[wtoconnor]

(In [7590]) Removed second article type that was showing up in the extended feed.

Addresses #1126

[russ]

i still get 2 article types at r7608 (also confirmed with a local build to exclude any packaging issues on branch)

 http://ploscompbiol-branch.plos.org:8080/article/feed?type=Issue&issue=info%3Adoi%2F10.1371%2Fissue.pcbi.v02.i01&extended=true

[wtoconnor]

(In [7609]) Removed second article type that was showing up in the extended feed.

Addresses #1126

[russ]

verified!