refactored constant ID_KEY to KEY_ID, added KEY_TYPE
maui namespace is now always lowercase
docs
model poliphony - get an object of class by _type field
new schema definition: '@extends' to import schema from parent class and specify only the additional part of schema
named instances trait

new validator - DomainName
schema attributes are now validated as arrays, even if scalars (cast to array while validating)
new validators: toArray and toAssoc
Merge branch 'master' of /var/www/maui
fixed missing param for param apply
added enforced field _type with its validator
added beforeSave() functionality to be defined in validators