Add version numbers; make app title configurable

public/static/style.css

@@ -57,15 +57,32 @@ header {
     margin: 1rem;
     padding: 0 1rem;
     display: flex;
+    flex-flow: row wrap;
     justify-content: space-between;
     align-content: center;
-    align-items: center;
+    align-items: baseline;
 }
 
-header h1 {
+header > * {
     margin: 1rem;
 }
 
+header > .header_appversion {
+    font-size: 0.75rem;
+    color: #767676;
+}
+
+header > .header_appversion > a {
+    color: inherit;
+}
+
+header > .header_spacer {
+    width: 0;
+    margin: 0;
+    padding: 0;
+    flex: 1 0 0;
+}
+
 /* -- Navigation bar -- */
 nav {
 }