Add Swedish language (#65)

Author: ludvigalden

lang/sv.css

@@ -0,0 +1,4 @@
+:lang(sv) .theorem::before { content: 'Sats ' counter(theorem) '. ' !important; }
+:lang(sv) .lemma::before { content: 'Lemma ' counter(theorem) '. ' !important; }
+:lang(sv) .proof::before { content: 'Bevis. ' attr(title) !important; }
+:lang(sv) .definition::before { content: 'Definition ' counter(definition) '. ' !important; }

languages.html

@@ -54,6 +54,7 @@ <h5>Abstract</h5>
       <option value="ro">Romanian (ro)</option>
       <option value="ru">Russian (ru)</option>
       <option value="sl">Slovenian (sl)</option>
+      <option value="sv">Swedish (sv)</option>
       <option value="tr">Turkish (tr)</option>
       <option value="zh-hans">Simplified Chinese (zh-hans)</option>
       <option value="zh-hant">Traditional Chinese (zh-hant)</option>