card_handler: make reader (sl) operations optional.

The constructor gets an sl object on initalization. The card handler
will then carry out the reader operation wait_for_card().

In cases where an mechanically automated card reader is used it may
be useful to go without those operations and let the caller carry out
the appropriate reader operations. So Lets make the sl object
optional for the CardHandlerAuto class. If it is not present, simply
do not carry out the pre programmed reader operation.

Change-Id: I0f793aec51751b7c7b87d55b66326cce9970274e
Related: SYS#5617
diff --git a/pySim/card_handler.py b/pySim/card_handler.py
index ef1b071..385c55e 100644
--- a/pySim/card_handler.py
+++ b/pySim/card_handler.py
@@ -94,7 +94,8 @@
 	def get(self, first = False):
 		print("Ready for Programming: Transporting card into the reader-bay...")
 		self.__exec_cmd(self.cmds['get'])
-		self.sl.connect()
+		if self.sl:
+			self.sl.connect()
 
 	def error(self):
 		print("Programming failed: Transporting card to the error-bin...")