Add support for a configuration file.

Adding a coniguration file (/etc/sysmon.ini).  This will allow users to
no monitor the temperature of speciic drives by ignoring them, as well
as ignoring the performance from specific drives.

For instance on a system running mdraid, you could ignore performance on
all of the drives that make up the raid array, and ignore the
temperature of the raid device.

monitor/test.ini

@@ -0,0 +1,5 @@
+[temperature]
+   ignore = "mmcblk0"
+
+[performance]
+   ignore = "mmcblk0"