Fan and TachSensor class introduction

A Fan object has one or more TachSensor objects.

The TachSensor class is used to keep track of the
the actual and expected speeds.  It only tracks
expected speeds if the _hasTarget attribute is true.

Future commits will add more functionality.

Change-Id: I9bb5fac39f25c5c31c18457ebedf82838fcf6641
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
5 files changed