Add temperature compensation

A new tempcomp directive can be used to specify a file for reading
current temperature, update interval and compensation coefficients. The
clock frequency corrections are applied in local module and are invisible
in upper layers. The measurements and corrections can be logged to
tempcomp.log file.

logging.c

@@ -58,7 +58,7 @@ struct LogFile {
 static int n_filelogs = 0;
 
 /* Increase this when adding a new logfile */
-#define MAX_FILELOGS 5
+#define MAX_FILELOGS 6
 
 static struct LogFile logfiles[MAX_FILELOGS];