Updated the DumpInfo example

Updated the `DumpInfo.ino` example sketch/program:
* Changed the description, to show that it is an example for the MFRC522 library
* Added link to the GitHub based project for the MFRC522 library
* Expanded the description of the example: what is does, basic instructions to use it (and how to see the output it generates...); and what to expect in some situations
* Updated the pin layout based on #48 updated README
* Added a `ShowReaderDetails()` called from the ``setup()` to output the MFRC522 software version information, as described in #27; which should also help detect any misconfiguration