Code tidy
Remove unnecessary definitions
Universal hooks

Hooks defined on `sequelize` are applied universally on all models

Universal hooks 2

Universal hooks 2

Universal hooks 2

universal hooks 6
Hooks run sync in sync functions
Hooks on Sequelize#define

define hooks 2

define hooks 3

define hooks 4

define hooks 7
Hooks on Sequelize()

hooks9

hooks10
Tests for universal hooks
Tests for Sequelize#define hooks
Tests for Sequelize() hooks
Tests made sync
Tests return promises
Sequelize() hooks change name Instantiate to Init
Merge pull request #2320 from overlookmotel/universal-hooks

Universal hooks for all models + hooks on Sequelize#define and Sequelize()