Add preliminary report system

The report system is pretty low-tech. However the scaffolding is there
for a lot of new stuff. What we currently have:

* Users can create reports
* Staff can view reports
* Admins can create report templates

There's a post drop-down menu available on all posts now, too. This is
where "report post" menu item lives and other things like that can be
added too.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/static/board/style.css

@@ -1,3 +1,7 @@
+body {
+    background-color: #ededed;
+}
+
 hr {
     color: #ededed;
 }
@@ -26,7 +30,29 @@ hr {
     text-align: center;
 }
 
-/* Posts */
+.post_menu {
+    position: absolute;
+    background: #ededed;
+    outline: 1px solid #555;
+}
+
+.post_menu_items {
+    list-style-type: none;
+    padding: 0;
+    margin: 0;
+}
+
+.post_menu_item {
+    padding: 3px;
+}
+
+.post_menu_button {
+    text-decoration: none;
+}
+
+/*******************************************************************************
+ Posts
+********************************************************************************/
 /*.post_body { }*/
 .post_image_info {
     font-size: small;