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
typeTo => discriminator
polymorphics can now be declared using object
Updated remaining relations to use polymorphicParams
Merge pull request #195 from lchenay/patch-3

Fix HEAD on relation hasMany
Export GeoPoint class
Remove unused data
Increase the max number of model listeners

See https://github.com/strongloop/loopback/issues/404
Merge branch 'feature/polymorphic-rel' of github.com:fabien/loopback-datasource-juggler into fabien-feature/polymorphic-rel
Fix test cases
Merge branch 'fabien-feature/polymorphic-rel'
Merge branch 'master' of github.com:strongloop/loopback-datasource-juggler into 2.0-patched

Conflicts:
	lib/relation-definition.js