Yet another iteration on the user interface

* Automatically display the overlay when the card details is opened
  (previously we waited for the mouse to enter the card details panel)
* Improve the design of the minicards badges
* Change the minicard background when it is hovered or selected
* Removes unimplemented features links from the UI
* Fix the board canvas position when the sidebar is open (was hidden
  behind)

Fixes #215

client/components/boards/boardBody.styl

@@ -26,11 +26,10 @@ position()
       animation: fadeIn 0.2s
       z-index: 16
 
-    &.next-sidebar
+    &.is-sibling-sidebar-open
       margin-right: 248px
 
     &.is-dragging-active
-
       .open-minicard-composer,
       .minicard-wrapper.is-checked
         display: none
@@ -39,14 +38,8 @@ position()
     align-items: flex-start
     display: flex
     flex-direction: row
-    margin-bottom: 10px
-    overflow: auto
-    padding-bottom: 5px
+    margin: 0 10px 10px
+    padding: 0 25px 5px 0
+    overflow-x: auto
+    overflow-y: hidden
     position: cover
-
-    // In order for the card details pane to overlap the header we need to
-    // virtually increase this container size with the below hack. (Note that it
-    // is not possible to set overflow-x: auto, overflow-y: hidden as I
-    // originally tried).
-    padding-top: 10px
-    top: -10px