message: update readme to ensure it says that it requires SerialFlash
diff: @@ -14,7 +14,7 @@ Requirements
  **Arduino IDE (Windows/Linux)**: To program the Tympan, you need to download and install the [Arduino IDE](https://www.arduino.cc/en/Main/Software). Download the actual Arduino IDE, don't use the online web-based editor. After installing the Arduino IDE, open the shortcut so that it fully initializes. Then, you can close it down and move to the next step, which is...
  -**Teensyduino Add-On (Windows/Linux, MASTER branch)**: After installing the Arduino IDE, you need to download and install the [Teensyduino Add-On](https://www.pjrc.com/teensy/td_download.html), which allows you to program Teensy devices (including Tympan) using the Arduino IDE. It'll ask you whether you want to install a bunch of libraries. You can say "yes" to them all, or you can say "yes" to just a few (like Audio, Bounce2, FreqCount, FreqMeasure, i2c_t3, SerialFlash, Snooze, and SPIFlash). It's your choice.
  +**Teensyduino Add-On (Windows/Linux, MASTER branch)**: After installing the Arduino IDE, you need to download and install the [Teensyduino Add-On](https://www.pjrc.com/teensy/td_download.html), which allows you to program Teensy devices (including Tympan) using the Arduino IDE. It'll ask you whether you want to install a bunch of libraries. You can say "yes" to them all, or you can say "yes" to these few: Audio, Bounce2, FreqCount, FreqMeasure, i2c_t3, SerialFlash, Snooze, and SPIFlash.
  **Teensyduino (Mac, MASTER branch)**: Recent versions of OS X do not support the Teensyduino Add-On installer, so there is a full [Teensyduino IDE](https://www.pjrc.com/teensy/td_download.html) available from the Teensy project which just needs to be downloaded and extracted from its ZIP file.
  