Made _email, _hash & _imageUrl final
Reverted last change (removed final)
Made _email, _hash & _imageUrl final
Update gravatar.dart
Moved _generateHash outside of Gravatar class
Moved _imageUrl to imageUrl method, made _email & _hash private
Added toString method, using codeUnits now
Increased minor version to 1.2.0
moved unittest to dev dependencies
specified unittest version and updated package version