Add a Timer class

The class provides for a timer, callback invocation on timer expiry, and
timer control/cleanup. This will be used in subsequent commits.

Change-Id: Ieb04e5ec76a1023efa2c3f5c5b88f03e9819c3eb
Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index aaa55bf..932e4e2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -23,6 +23,7 @@
 	sysfs.cpp \
 	env.cpp \
 	fan_speed.cpp \
-	fan_pwm.cpp
+	fan_pwm.cpp \
+	timer.cpp
 
 SUBDIRS = . test msl