Describe origin and purpose.

- README: describe the project's origin and purpose
- bbl/bbl.c: corrected title

README

@@ -0,0 +1,15 @@
+Ben Blinkenlights
+=================
+
+This project is a proof of concept implementation of Rikard Lindstrom's
+idea of using the Ben's uSD slot as a general extension interface also
+for devices that don't speak MMC or SD/SDIO. The application is a simple
+LED circuit, as suggested by David Samblas.
+
+The uSD slot gives access to six GPIOs, a 3.3 V supply that can be
+switched on and off by software, and ground. We use a simple form of
+multiplexing to drive ten LEDs with this interface.
+
+Note that one should only light one LED at a time. If multiple LEDs are
+lit, they will share the current though the common resistor, and will
+thus be less bright than a single LED.

bbl/bbl.c

@@ -1,5 +1,5 @@
 /*
- * bbl.c - Read or write any CPU register
+ * bbl.c - Produce a "Knight Rider" effect on the LED board
  *
  * Written 2010 by Werner Almesberger <werner@openmoko.org>
  *