shell: Rename article to "Unix Shell tutorial"

It should hopefully stand out more / be clearer as to its contents,
among the ever-growing list of articles.
Infrared hardware: Add IguanaWorks USB IR transceiver

Information from Bryce Gibson on the mailing list:
https://groups.google.com/d/msg/stb-tester/yoI73vLnoIQ/JMQtwgD1bMEJ