[PLINK-608] - BasicModel.getGroup is not returning groups with a deep hierarchy.
Merge pull request #416 from pedroigor/master

[PLINK-608] - BasicModel.getGroup is not returning groups with a deep hierarchy.
[PLINK-609] - Remove complex schema module.
Merge pull request #417 from pedroigor/master

[PLINK-609] - Remove complex schema module.