added doctrine tags to reference
Merge pull request #2583 from pvolok/doctrine_tags

Added doctrine tags to the reference
Link to UserProviderInterface correction
Corrects exception controller name
Update introduction.rst

Changed $_FILE to $_FILES
Merge pull request #2612 from langj/fix-controller-name

Corrects exception controller name
add missing word
Update cookbook/form/data_transformers.rst

there is an added ';' in this line
->add('dueDate', null, array('widget' => 'single_text'))
in the end
Fixed build errors
Merge pull request #2632 from WouterJ/fix_build_errors

Fixed build errors
Removed extra backtick after link to method of the api documentation