Callback Vote Check 2.0

Some left over code from a previous version caused the page which explains things to not function properly.

• php 7.0+ support
• updated example page with updated php example
• updated example page to change MySQL to MySQLi
• admin settings have been removed ( ip whitelist ). As referrers can be easily fakes, this makes not much sense

• Added a security fix on the gateway page to prevent xss attacks.
• Plugin now uses proper VL 1.5 hit in checks
• New function, in case a user change his ip when voting, his username ( the one he want to get rewards for - found in url when provided ) is inserted along with users ip. So when the system determines the vote is unique, it next checks the database if the user has a entry for today already, and if so, overwrites hit in check unique variable so no vote happens

1) IP check function: This method was returning false positives, which has been taken care off.
2) 2 php notices of undefined variables have been fixed.
3) Added support to send voters ip to the script on members site.

Changed the update url in the info file to reflect our new plugins page.
This update is required if you want to run plugin version checks from within your admin panel, as the old update url is obsolete.