add unit tests for draft 3 'required' objects
fix failing 'required' testcase
refactor conditional logic of 'required' validation
types of draft 3 'required' properties are not checked when given as objects, add resp. unit tests
separate 'type' from 'required' validation, fixing failing unit tests
fix code style
fix use statement
remove duplicate draft3 'required' validation in Constraints\Object
fix duplicate call of checkUndefined
fix code style
Updated composer installation instructions
Added packagist badges
Merge pull request #55 from alexmmm/code-cleanup

Code cleanup
Merge pull request #57 from marcqualie/patch-1

Updated composer installation instructions
Merge pull request #58 from marcqualie/patch-2

Added packagist badges
Merge pull request #53 from alexmmm/fix-required-validation

Fix draft 3 'required' validation issues