Refactor variable substitution for receiving invoice numbers

Use localStorage to store selected printer
Add printer selection for invoice template
Print after sale checkbox is now present in receivings and sales screen
Remove print after sale options from receipt_config
Add default translations to receivings_lang.csv
Fix some bugs preventing to print and email at the same time

application/libraries/Sale_lib.php

@@ -78,6 +78,17 @@ class Sale_lib
 		return $this->CI->session->set_userdata('sales_invoice_number_enabled', $invoice_number_enabled);
 	}
 	
+	function is_print_after_sale() 
+	{
+		return $this->CI->session->userdata('sales_print_after_sale') == 'true' ||
+			$this->CI->session->userdata('sales_print_after_sale') == '1';
+	}
+	
+	function set_print_after_sale($print_after_sale)
+	{
+		return $this->CI->session->set_userdata('sales_print_after_sale', $print_after_sale);
+	}
+	
 	function get_email_receipt() 
 	{
 		return $this->CI->session->userdata('email_receipt');