BitTorrent Inc. Configuration Changes

Howdy tuxpoldo,

My name is Richard and I'm the Sync engineer responsible for packaging for NAS and other third parties.

I've made some some changes to the sync.conf's or equivalents to reflect the latest recommended settings I've been using for our NAS packages.

The changes are generally:
* Use `"display_new_version":false` instead of `"check_for_updates":false`
   * Unfortunately, `check_for_updates` is somewhat misnamed for what it does. What BitTorrent refers to as the CFU is how we collect usage information. When it is set to false we will not receive the statistics pings. With 1.4 we implemented the `display_new_version` field which does what you would think `check_for_updates` does. With `display_new_version` set to `false` we will not inform the user that there is a newer build of Sync available in-app. 
   * None of the POSIX builds of Sync have any sort of built-in auto-update mechanism; it has always just been an in-app notification of a newer available build.
   * By not specifying `check_for_updates` it will default to `true` which will allow us to have a more complete picture of the number of POSIX users we have. I hope to use this data to justify additional engineering resources for our POSIX builds.

* Specify `"vendor":"tuxpoldo"`
   * By specifying `"vendor":"tuxpoldo"` we will be able to segment out the the statistics pings of users of your Debian packages. 
   * I hope to be able to use this data to justify a more official packaging of Sync not just for Apt/Deb but also Yum/RPM.

* Not specifying any settings in sync.conf which are desired to be configured by users through the WebUI/API
   * Settings specified in sync.conf will eventually override whatever changes a user makes to them through the WebUI. As an example, by specifying `"download_limit":0` in sync.conf, any changes to the download rate limit done through the WebUI will not survive a restart.
   * Settings changes made in the WebUI which don't persist restart can be particularly frustrating for users.
   * Generally speaking, sync.conf should be as minimally configured as possible

I think I made these changes in all the places where they need to be made, but as I'm not completely familiar with this codebase I would greatly appreciate a review.

Thanks,
Richard