Remove the code about item table

Because we don't support `item` table now.

lib/td/client.rb

@@ -93,15 +93,6 @@ def create_log_table(db_name, table_name)
     @api.create_log_table(db_name, table_name)
   end
 
-  # @param [String] db_name
-  # @param [String] table_name
-  # @param [String] primary_key
-  # @param [String] primary_key_type
-  # @return [true]
-  def create_item_table(db_name, table_name, primary_key, primary_key_type)
-    @api.create_item_table(db_name, table_name, primary_key, primary_key_type)
-  end
-
   # Swap table names
   #
   # @param [String] db_name

lib/td/client/api/table.rb

@@ -32,36 +32,13 @@ def list_tables(db)
     return result
   end
 
-  # @param [String] db
-  # @param [String] table
-  # @param [String] type
-  # @return [true]
-  def create_log_or_item_table(db, table, type)
-    code, body, res = post("/v3/table/create/#{e db}/#{e table}/#{type}")
-    if code != "200"
-      raise_error("Create #{type} table failed", res)
-    end
-    return true
-  end
-  private :create_log_or_item_table
-
   # @param [String] db
   # @param [String] table
   # @return [true]
   def create_log_table(db, table)
     create_table(db, table, :log)
   end
 
-  # @param [String] db
-  # @param [String] table
-  # @param [String] primary_key
-  # @param [String] primary_key_type
-  # @return [true]
-  def create_item_table(db, table, primary_key, primary_key_type)
-    params = {'primary_key' => primary_key, 'primary_key_type' => primary_key_type}
-    create_table(db, table, :item, params)
-  end
-
   # @param [String] db
   # @param [String] table
   # @param [String] type

lib/td/client/model.rb

@@ -101,12 +101,6 @@ def create_log_table(name)
     @client.create_log_table(@db_name, name)
   end
 
-  # @param [String] name
-  # @return [true]
-  def create_item_table(name)
-    @client.create_item_table(@db_name, name)
-  end
-
   # @param [String] table_name
   # @return [Table]
   def table(table_name)