Implemented polymorphic hasMany
Implemented polymorphic hasAndBelongsToMany
Implemented polymorphic hasOne

Signed-off-by: Fabien Franzen <info@atelierfabien.be>
Minor cleanup
More hasAndBelongsToMany tests
Implemented polymorphic hasMany through inverse

Added option invert: true to enable inverse polymorphic hasMany
relations.

Fixed missing fk1 in query of HasManyThrough.prototype.exists.
Minor tweaks; pass-through properties/scope for hasAndBelongsToMany
Merge tag 'v2.1.1'

2.1.1
Implemented embedsMany relation
Added validation for embedded items (optional)
Minor fix
Test build of embedsMany
Require unique ids for embedded items
typeTo => discriminator
polymorphics can now be declared using object
Updated remaining relations to use polymorphicParams
Fix HEAD on relation hasMany
Merge pull request #195 from lchenay/patch-3

Fix HEAD on relation hasMany
Export GeoPoint class
Remove unused data