add default option 'use_extra_field'
add translation
change caching
add languages
add cache management
add docComments to class-cache.php	
add docComments and return values to class-backend.php
final commit for merging into master
add license.txt and readme.txt.md
add documentary
rename index.php to avatarplus.php (fix issue with translating tools)
add translation de_DE
add readme.txt for WordPress repository