Adding a new Issue to an existing Volume removes all Articles for all Issues in the existing Volume until ObjectCache and BrowseCache are cleared

[npeterson]

1) Log in to a Journal 2) Check some of the Volume/Issues/Articles and pick one Volume 3) Log in to Admin Panel 4) Add a new Issue to an existing Volume 5) Verify that all the Articles for all the Issues in the Volume never show in the Journal 6) Clear the ObjectCache? and BrowseCache? in the Admin Panel 7) Verify that all the Articles for all the Issues in the Volume now show correctly in the Journal

[dragisak]

(In [7548]) Get methods in entities should not set fields.

Because of lazy loading, all values in the entity might not be initialized when get method is called. So simpleCollection might not have been initialized when getArticleList is called.

Addresses #1201, #1215 and #1228

[rcave]

Verified that adding a new issue to an existing volume does not affect current articles or issues.