Initial read-daemon for hwmon entries

Discoveres hwmon entries for fans, input voltage, and temperature
sensors.  Polls entries on a 1s interval and displays a message to
stdout if one of the entries have changed.
diff --git a/sensorset.H b/sensorset.H
new file mode 100644
index 0000000..beb8446
--- /dev/null
+++ b/sensorset.H
@@ -0,0 +1,31 @@
+#ifndef __SENSORSET_H
+#define __SENSORSET_H
+
+#include <map>
+#include <set>
+#include <string>
+
+class SensorSet
+{
+    public:
+        typedef std::map<std::pair<std::string, std::string>,
+                         std::set<std::string>> container_t;
+
+        SensorSet(const std::string& path);
+
+        container_t::const_iterator begin()
+        {
+            return const_cast<const container_t&>(container).begin();
+        }
+
+        container_t::const_iterator end()
+        {
+            return const_cast<const container_t&>(container).end();
+        }
+
+    private:
+        container_t container;
+
+};
+
+#endif