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/directory.C b/directory.C
new file mode 100644
index 0000000..5be9ff1
--- /dev/null
+++ b/directory.C
@@ -0,0 +1,38 @@
+#include <cerrno>
+#include <cstring>
+#include <iostream>
+#include "directory.H"
+
+Directory::Directory(const std::string& path) : entry(nullptr)
+{
+    dirp = opendir(path.c_str());
+    if (NULL == dirp)
+    {
+        auto e = errno;
+        std::cerr << "Error opening directory " << path.c_str()
+                  << " : " << strerror(e) << std::endl;
+    }
+}
+
+Directory::~Directory()
+{
+    if (dirp)
+    {
+        closedir(dirp);
+    }
+}
+
+bool Directory::next(std::string& name)
+{
+    if (!dirp) return false;
+
+    dirent entry;
+    dirent* result;
+
+    auto rc = readdir_r(dirp, &entry, &result);
+
+    if ((rc) || (NULL == result)) return false;
+
+    name = entry.d_name;
+    return true;
+}