Merge pull request #489 from sergeyklay/master

Proctected admin menu
Fixed issue: Fixed typo
Updated feature: Added user guide for Gleez Gravatar
Updated feature: Improved User::getAvatar - added 'is_gravatar' for template
Fixed issue: Cleanup gravatar config
Updated translation: Fixed Russian
Updated feature: Improved avatar view
Updated feature #482: Gleez Gravatar v1.3.0

+ Added: New helper Gravatar::getImage - Creates a image link
+ Added: Added user guide, see guide/gleez/gravatar

+ Updated: Gravatar::getRating use strtolower
+ Updated: Gravatar::setRating use not case sensitive param
+ Updated: Gravatar::setForceDefault by default use TRUE, now $force is optional

+ Fixed: API doc
+ Fixed: Default size of the returned gravatar now is 250px
+ Fixed: Maximum size of gravatars is 2048 instead 600
+ Fixed: Gravatar::buildURL - Fix incorrect construction of the URL::query
Updated feature: Cerber Theme