Add support for magazines, backend only (#53)

* Initial work to support magazines

* Change editor default height to 300px from 500px

* Stabilize the magazine repository app

* Switch from stacked to tabular inlines for magazines

* Update submodules

ram/bookshelf/static/admin/js/magazine_issue_defaults.js

@@ -0,0 +1,16 @@
+document.addEventListener('formset:added', function(event) {
+  const newForm = event.target; // the new inline form element
+
+  const defaultLanguage = document.querySelector('#id_language').value;
+  const defaultStatus = document.querySelector('#id_published').checked;
+
+  const languageInput = newForm.querySelector('select[name$="language"]');
+  const statusInput = newForm.querySelector('input[name$="published"]');
+
+  if (languageInput) {
+      languageInput.value = defaultLanguage;
+  }
+  if (statusInput) {
+    statusInput.checked = defaultStatus;
+  }
+});