Merge pull request #18 from a-x-/develop

add Russian translation file
Update CHANGELOG.md
Update PHPMailer.php from version 5.2.7 to 5.2.8
Update PHPMailer SMTP from version 5.2.7 to 5.2.8
Update CHANGELOG.md
Update CHANGELOG.md
Update getGravatarImageUrl PHPDoc.
Check captcha when registerNewUser calls (i had php notice caught).