WooCommerce Opt-In Tracker

How this will work is upon installation of WC 2.3 and up the admin will be prompted with a banner asking them wether they want to opt-in to sending non sensitive data to WooThemes http://cld.wthms.co/wZPY

If they select to opt-in it makes an immediate call to the WooThemes API endpoint, and then issues the user with a one-time discount coupon via email. The email is sent to the WordPress admin email as defined in the WordPress general settings, the discount can only be used with that email address.

@BFTrick can you check if you are happy with the general WooCommerce settings we track? Perhaps some settings we are missing and want to add?

To sum it up we keep track of the following data on each call the the API:
* Admin Email - only used for sending the coupon
* Site URL
* Theme Name
* Theme Version
* If child theme is used
* If theme declares WC support
* WP Version
* WP Memory Limit
* WP Debug Mode
* WP Locale
* If WP multisite
* Server Software
* PHP Version
* PHP Limits, ie max post size, time, input vars and if suhosin is installed
* PHP Modules, check if curl, fsockopen and soap is activated on server
* List of active plugins
* List of inactive plugins
* User counts
* Product counts
* Order counts
* Active payment gateways and what they support, ie subscriptions, pre-orders
* Active shipping methods
* Template overrides
* General WC settings, ie currency, base location, weight unit, dimension unit, download method etc.

@mikejolley @claudiosmweb Please leave this pull request open until everyone is happy and I give the go ahead to merge :smiley:

Feel free to make recommendations where you guys see fit.