mbed_app.json configured to operate on senet

To enable cayenne, edit mbed_app.json, assign pins for desired function

Example:

        "cayenne": {
            "help": "compile main_cayenne.cpp instead of main.cpp",
            "value": 1
        },
        "analog_in_pin": {
            "help": "PA_0, PA_4, PA_5",
            "value": "PA_0"
        },
        "analog_out_pin": {
            "help": "PA_0, PB_5, PB_10, PB_11",
            "value": "PB_11"
        },
        "_digital_out_pin": {
            "help": "",
            "value": ""
        }
Revision:
55:6f2e16ebde99
Parent:
52:1bd775571014
Child:
57:36e87c44c920
--- a/README.md	Tue Jul 23 12:04:56 2019 +0100
+++ b/README.md	Tue Aug 20 15:01:49 2019 +0100
@@ -97,7 +97,7 @@
 
 ## Module support
 
-Here is a nonexhaustive list of boards and modules that we have tested with the Mbed OS LoRaWAN stack.
+Here is a nonexhaustive list of boards and modules that we have tested with the Mbed OS LoRaWAN stack:
 
 - MultiTech mDot.
 - MultiTech xDot.
@@ -105,6 +105,10 @@
 - Advantech Wise 1510.
 - ST B-L072Z-LRWAN1 LoRa®Discovery kit (with muRata radio chip).
 
+Here is a list of boards and modules that have been tested by the community:
+
+- IMST iM880B.
+
 ## Compiling the application
 
 Use Mbed CLI commands to generate a binary for the application.