add tests for table grid sizing, solve bugs in fluid table grid sizing

less/tables.less

@@ -147,7 +147,15 @@ table {
 // TABLE CELL SIZING
 // -----------------
 
-// Change the columns
+// Reset default grid behavior
+table [class*=span],
+.row-fluid table [class*=span] {
+  display: table-cell;
+  float: none; // undo default grid column styles
+  margin-left: 0; // undo default grid column styles
+}
+
+// Change the column widths to account for td/th padding
 table {
   .span1     { .tableColumns(1); }
   .span2     { .tableColumns(2); }