Fix up hover script and improve bootloading.

lib/sensors.ks

@@ -0,0 +1,26 @@
+
+// we rebuild the sensor list with every invocation, because things change
+function buildSensorList {
+  local sList is Lexicon().
+  list SENSORS in SensorList.
+  for s in SensorList {
+    sList:add(s:type, s).
+  }
+  return sList.
+}
+
+function HasSensor {
+  parameter s.
+  local sList is buildSensorList().
+  return sList:HasKey(s).
+}
+
+function ReadSensor {
+  parameter s.
+
+  local sList is buildSensorList().
+  if not sList:HasKey(s) {
+    return -1. // TODO: is -1 an impossible result for all sensors? I suspect not...
+  }
+  return sList[s].
+}