Center the name input of a public edit

Fixes #237
Else it looks rather out of place

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

css/style.css

@@ -520,3 +520,7 @@ document p{
 .oc-dialog .oc-dialog-buttonrow .cancel {
 	float:left;
 }
+
+#documents-content {
+	margin: 0px auto;
+}