updated readme

README.md

@@ -6,7 +6,7 @@ Shop: [FTDI-Breakout](http://www.watterott.com/en/FTDI-Breakout-Reloaded-V11)
 ![FTDI-Breakout](https://raw.github.com/watterott/FTDI-Breakout/master/img/ftdi-breakout.jpg)
 
 ## Features
-* 3V3 or 5V logic/supply voltage selectable by switch
+* 3.3V or 5V logic/supply voltage selectable by switch
 * Overcurrent protection (resettable polyswitch fuse)
 * Standard 6 pin FTDI connector (for Arduino)
 * Standard 4 pin Prop Plug connector (for Parallax Propeller and Basic-Stamps)