smuxi_hooks/on-message-received/print_msg.sh: don't block the caller

If the printer queue is full because it waits for paper for example, lpr will
block the caller and with that Smuxi. Queue the print job as a background
process instead.

Author: meebey

smuxi_hooks/on-message-received/print_msg.sh

@@ -22,4 +22,4 @@ echo -n "$SMUXI_SENDER " | lpr
 send_esc 5 # Cancel italic
 echo $SMUXI_MSG \
 	| iconv -f utf-8 -t 437 -c \
-        | lpr
+        | lpr &