Added date validation to resources.
Added default timezone configuration
Implemented WRITE callback for properties
Refactored ORM core functionality to increase speed.
Bugfix
Added support for null values on insert.
Set Page::parentId to null as default
Enabled null values for update queries
Rendering child page widgets when a page is rendered as JSON
Removed redundant function call.
Refactoring
Enabled rules for collections and add READ_ONLY rules to Node::children and Page::children
Merge branch 'master' into stage