added sensor reading utility

sensors.py

@@ -0,0 +1,20 @@
+import os, json, sys
+
+try:
+    sensor_group = sys.argv[1]
+    sensor = sys.argv[2]
+except IndexError:
+    print("usage: python3 "+sys.argv[0]+" <sensor group> <sensor>")
+    sys.exit(1)
+
+sensors_process = os.popen("sensors -j")
+temps_str = sensors_process.read()
+sensors_process.close()
+
+temps = json.loads(temps_str)
+
+try:
+    print([value for key, value in temps[sensor_group][sensor].items() if key.endswith("input")][0])
+except KeyError:
+    print("Sensor \""+sensor_group+":"+sensor+" not found!")
+    sys.exit(1)