Remove legacy test code, add a licence and a readme file.

Author: ZeWaren

Diff for: LICENCE

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+Copyright 2020 Erwan Martin
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Diff for: Makefile

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+# IZAR I R4 PRIOS meter collector
+
+![izar_rc_i_r4](doc/IZAR_RC_I_R4.jpg "A IZAR counter") ![STEVAL-FKI868V2](doc/steval-fki868v2.jpg "STEVAL-FKI868V2")
+
+## Introduction
+
+This project contains the implementation of a Wireless M-Bus (WMBus) collector for DIEHL IZAR I R4 smart meters, running
+on a ST-Micro [STEVAL-FKI868V2](https://www.st.com/en/evaluation-tools/steval-fki868v2.html) kit (a [NUCLEO-L053R8](https://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-mpu-eval-tools/stm32-mcu-mpu-eval-tools/stm32-nucleo-boards/nucleo-l053r8.html) board with a [S2-LP](https://www.st.com/content/st_com/en/products/wireless-transceivers-mcus-and-modules/sub-1ghz-rf/s2-lp.html) 868MHz transceiver).
+
+### Supported smart meters
+
+- DIEHL Metering (ex SAPPEL) IZAR 868 I R4 LIGHT
+
+Many more devices should be supported (probably most if not all DIEHL PRIOS smart water meters).
+
+Please report yours if you tested them.
+
+## Usage
+
+### General
+
+Build the application using your favorite IDE (an IAR/EWARM workspace is provided).
+
+Flash the firmware into the Cortex M0 microcontroller.
+
+Plug the board into a computer using a USB connector.
+
+Open the USB virtual COM port provided by the board, with speed 115200.
+
+The device outputs every smart meter readings in real time:
+    
+    # socat open:/dev/cuaU0,raw,echo=0,ispeed=115200,ospeed=115200 -
+    20d51a73,100750,99935
+    20d52c1a,330604,329942
+    20d53a72,65299,64680
+    20d54c16,92546,92277
+    20d55c1e,102543,101646
+    20d56c1d,91966,90586
+    20d577ca,80416,77826
+
+The format is: `[device identifier],[current_reading],[last_month_reading]`, with both readings in cubic meters (m3).
+
+### Shell
+
+Logging the values for a specific meter in a file, prepending each line with the current timestamp can be done with some
+shell scripting:
+
+    socat open:/dev/cuaU0,raw,echo=0,ispeed=115200,ospeed=115200 - | grep 20d78c1e | awk '{cmd="date +%s"; (cmd | getline date); close(cmd); print date "," $1}' >> /var/log/izar_local.log
+
+### Python
+
+Reading the values in Python is trivial as well:
+
+```
+import serial
+with serial.Serial('/dev/cuaU0', 115200, timeout=60) as ser:
+    while True:
+       line = ser.readline()
+       if not line:
+           continue
+       data = line.split(',')
+       print('Meter {}: current={}m3, last_month={}m3'.format(data[0], float(data[1]) / 1000, float(data[2]) / 1000))
+```
+
+```
+Meter 20d51c16: current=92.546m3, last_month=92.277m3
+Meter 20d52c1d: current=91.966m3, last_month=90.586m3
+Meter 20d53c1e: current=102.543m3, last_month=101.646m3
+Meter 20d547c6: current=77.408m3, last_month=76.001m3
+Meter 20d55a73: current=100.75m3, last_month=99.935m3
+Meter 20d56c1c: current=301.664m3, last_month=300.839m3
+```
+
+## Authors
+
+Erwan Martin <[email protected]>
+
+The logic to decrypt and decode the PRIOS protocol is originally from Jacek Tomasiak.
+
+## Licence
+
+The application code is protected by licence [BSD-3-Clause](https://opensource.org/licenses/BSD-3-Clause).
+
+The project uses C libraries provided by STMicroelectronics, which are protected by their own licences.