Fix recipe to run on Windows

- Only stop w32tm if we don't need it anymore.
- Call w32tm /update after starting it (command fails if it's not
  running)
- Fix passing the list of ntp servers to w32tm.
Merge pull request #37 from vuntz/fix-windows

Fix recipe to run on Windows
Merge pull request #40 from jtwill98/pull-req-release-roxy-master-17620546f850dd64dddb20c9c812824cc5589804

Merge of Latest Pebble commits into Roxy [6/13]