ValidatorTemplate class name changed to more meaningful FileValidator, as it validates file by file.
Created MultipleFilesValidator that can validate a bunch of files from the same group
GroupValidator created. It can validate a whole group.
Merge branch 'master' of github.com:n-educatio-pl/CheckCheckIn

Conflicts:
	src/michaelszymczak/CheckCheckIn/Test/Validator/MultipleFilesValidatorShould.php
	src/michaelszymczak/CheckCheckIn/Test/Validator/ValidatorFactoryShould.php
	src/michaelszymczak/CheckCheckIn/Validator/MultipleFilesValidator.php
	src/michaelszymczak/CheckCheckIn/Validator/ValidatorFactory.php