IOT-1583: Adding /W4 and /WX to timer build.

IOT-1583: Adding /W4 and /WX to timer build.

Making sure any version changes of timer don't introduce
level 4 warnings.

I'm also changing the return value of StartRetransmit() inside
ca_adapter_net_ssl.c, since it's being used as a timer callback,
which doesn't return any values. Nowhere in the code was the returned
value of that function read.

Change-Id: Ic401ae27c5af46b05a21868dfa0c020ee6429f20
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17513
Reviewed-by: Alex Kelley <alexke@microsoft.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Mike Fenelon <mike.fenelon@microsoft.com>