Refactor the model initialization step & generalize attributes inheritance on non array.
Merge pull request #979 from jails/refactor/model-inherited-attributes

Refactor the model initialization step & generalize attributes inheritance on non array.
Change naming for model attribute inheritance.
Merge pull request #980 from jails/refactor/model-inherited-typo

Change naming for model attribute inheritance.
HABTM Model relationship support for READ queries using `Database` datasources.
Save relations implementation.