Update attributes extend method

[ishannz]

changes

• Add a new hook called updateAttributes to update the $attributes
• Limit the last chars to 12 on GUID to fix the validation error under validGuid function checking this preg_match /^[A-F0-9]{8}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{12}?$/i. According to this, the last chars should be 12

Please create a new tag after this and merge this to the master as well.

[satrun77]