Do not overwrite inclusion but scope them. Needed in relation hasManyThrought
Add test to protect the use of include in related method
Allow to set collect key from relation definition.

This is needed when declaring a relation hasManyThrough from and to the same classe.

Exemple: 
2 class Profile and Follow

Follow have 2 columns: followingId, followeeId

app.models.profile.hasMany(app.models.profile, {
    through: app.models.follow,
    as: 'followers',
    foreignKey: 'followerId',
    collect: 'follower'
});

app.models.profile.hasMany(app.models.profile, {
    through: app.models.follow,
    as: 'followees',
    foreignKey: 'followeeId',
    collect: 'followee'
});
Merge branch 'patch-2' into 2.0-patched
Merge branch 'patch-4' into 2.0-patched