moved select_manager to it's own file

Author: Anna

lib/arel/select_manager.rb renamed to lib/arel/select_manager_sqlserver.rb

@@ -1,6 +1,25 @@
 require 'arel'
-
+require 'arel/select_manager_sqlserver'
 module Arel
+
+  module Nodes
+
+    # Extending the Ordering class to be comparison friendly which allows us to call #uniq on a
+    # collection of them. See SelectManager#order for more details.
+    class Ordering < Arel::Nodes::Unary
+      def hash
+        expr.hash
+      end
+      def ==(other)
+        other.is_a?(Arel::Nodes::Ordering) && self.expr == other.expr
+      end
+      def eql?(other)
+        self == other
+      end
+    end
+
+  end
+
   module Visitors
     class SQLServer < Arel::Visitors::ToSql
 
@@ -9,6 +28,7 @@ class SQLServer < Arel::Visitors::ToSql
       # SQLServer ToSql/Visitor (Overides)
 
       def visit_Arel_Nodes_SelectStatement(o, a)
+        puts "o.cores.size#{o.cores.size}" unless o.cores.size < 2
         if complex_count_sql?(o)
           visit_Arel_Nodes_SelectStatementForComplexCount(o, a)
         elsif o.offset