IOT-1583: Temporary fix for remaining /W3 warnings.

IOT-1583: Temporary fix for remaining /W3 warnings.

This change suppresses some of the remaining /W3 VS compiler warnings,
fixes for which are too intrusive to meet the 1.3-rel bar.

In addition to that we're enabling the /WX compiler option
to prevent any new /W3 warnings from being checked in.

Change-Id: I061bc1c83615e052d77f8eb6b96fd488d1f49e4b
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/20487
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>