Overhaul tables docs and use rgba() colors for inverse tables

- Add inverse examples for all variants
- Use rgba() colors for hover and accent states for easy usage in inverse styles

scss/_tables.scss

@@ -99,6 +99,41 @@
 @include table-row-variant(danger, $state-danger-bg);
 
 
+// Inverse styles
+//
+// Same table markup, but inverted color scheme—dark background and light text.
+
+.thead-inverse {
+  th {
+    color: #fff;
+    background-color: $gray-dark;
+  }
+}
+
+.thead-default {
+  th {
+    color: $gray;
+    background-color: $gray-lighter;
+  }
+}
+
+.table-inverse {
+  color: $gray-lighter;
+  background-color: $gray-dark;
+
+  th,
+  td,
+  thead th {
+    border-color: $gray;
+  }
+
+  &.table-bordered {
+    border: 0;
+  }
+}
+
+
+
 // Responsive tables
 //
 // Wrap your tables in `.table-responsive` and we'll make them mobile friendly
@@ -118,35 +153,6 @@
 }
 
 
-.thead-inverse {
-  th {
-    color: #fff;
-    background-color: $gray-dark;
-  }
-}
-.thead-default {
-  th {
-    color: $gray;
-    background-color: $gray-lighter;
-  }
-}
-
-.table-inverse {
-  color: $gray-lighter;
-  background-color: $gray-dark;
-
-  &.table-bordered {
-    border: 0;
-  }
-
-  th,
-  td,
-  thead th {
-    border-color: $gray;
-  }
-}
-
-
 .table-reflow {
   thead {
     float: left;