Fixed a missed ruleset.last occurence.

Signed-off-by: matematik7 <domen.ipavec@z-v.si>
Added propertyValidate rule.

Signed-off-by: matematik7 <domen.ipavec@z-v.si>
Added duplicatedProperties rule.

Signed-off-by: matematik7 <domen.ipavec@z-v.si>