fix table border bug with double borders on theads and use of colgroup

docs/assets/css/bootstrap.css

@@ -1174,8 +1174,10 @@ table {
 .table thead th {
   vertical-align: bottom;
 }
-.table thead:first-child tr th,
-.table thead:first-child tr td {
+.table colgroup + thead tr:first-child th,
+.table colgroup + thead tr:first-child td,
+.table thead:first-child tr:first-child th,
+.table thead:first-child tr:first-child td {
   border-top: 0;
 }
 .table tbody + tbody {
@@ -1198,12 +1200,6 @@ table {
 .table-bordered td {
   border-left: 1px solid #dddddd;
 }
-.table-bordered thead:first-child tr:first-child th,
-.table-bordered tbody:first-child tr:first-child th,
-.table-bordered tbody:first-child tr:first-child td {
-  border-top: 0;
-  border-bottom: 1px solid #dddddd;
-}
 .table-bordered thead:first-child tr:first-child th:first-child,
 .table-bordered tbody:first-child tr:first-child td:first-child {
   -webkit-border-radius: 4px 0 0 0;

docs/base-css.html

@@ -435,6 +435,10 @@ For example, <code>section</code> should be wrapped as inline.
   <div class="row">
     <div class="span8">
       <table class="table table-bordered table-striped">
+        <colgroup>
+          <col class="span1">
+          <col class="span7">
+        </colgroup>
         <thead>
           <tr>
             <th>Tag</th>

docs/templates/pages/base-css.mustache

@@ -359,6 +359,10 @@
   <div class="row">
     <div class="span8">
       <table class="table table-bordered table-striped">
+        <colgroup>
+          <col class="span1">
+          <col class="span7">
+        </colgroup>
         <thead>
           <tr>
             <th>{{_i}}Tag{{/i}}</th>

less/tables.less

@@ -37,8 +37,10 @@ table {
     vertical-align: bottom;
   }
   // Remove top border from thead by default
-  thead:first-child tr th,
-  thead:first-child tr td {
+  colgroup + thead tr:first-child th,
+  colgroup + thead tr:first-child td,
+  thead:first-child tr:first-child th,
+  thead:first-child tr:first-child td {
     border-top: 0;
   }
   // Account for multiple tbody instances
@@ -77,8 +79,6 @@ table {
   thead:first-child tr:first-child th,
   tbody:first-child tr:first-child th,
   tbody:first-child tr:first-child td {
-    border-top: 0;
-    border-bottom: 1px solid @tableBorder;
   }
   // For first th or td in the first row in the first thead or tbody
   thead:first-child tr:first-child th:first-child,