add readme

Signed-off-by: Steve Markgraf <steve@steve-m.de>

README

@@ -0,0 +1,6 @@
+rtl-sdr
+Software to turn the Realtek RTL2832U into a SDR
+======================================================================
+
+For more information see:
+http://sdr.osmocom.org/trac/wiki/rtl-sdr