Instead or additionally to an email address, a MediaWiki user name can now be specified.
Described that this is a fork and added my name so that Christian Weiske is not blamed for any errors I introduce.
Fixed: width was given twice in the image element.
Used ParserFirstCallInit as initialization function and avoided the use $wgParser as global variable.
Removed email addresses from $wgExtensionCredits because this is what other extensios do as well; the addresses are in the source code anyway.
Explicitly defined user setting variables and used global $x instead of $GLOBALS['x'].
Changed the position of the parser hook definition.
Restructured parsing of attributes. This way it's clearer to me.
Separated parsing and using the Services_Libravatar library.
Now HTML is created with DOM classes instead of manual creation.
Now the result is returned with markerType nowiki to prevent wiki formatting.