rdrlist is a simple program that makes a connection to PC/SC lite, 
repeatedly calling SCardListReaders() inside an infinite loop, in order
to get the current list of readers. 

The (VT100 compatible) screen, for which this utility's output
is designed to deliver content to,  is refreshed at each cycle,
such that at any point in time the current readers known by
PC/SC lite are shown on the screen.

An ASCII spinner is displayed to remind the user that the program
is actively monitoring the reader list, even if the reader list
isn't actually changing.

