custom yeoman subgenerator templates on a project by project basis

Added feature to allow custom yeoman sub generator templates on a project by project basis.
Example. To use this feature, ensure you have a .yo-rc.json file in your project root directory. Then add subgenerator properties that point to your projects custom templates. Respective: "directiveComplexTemplates", "directiveSimpleTemplates", "filterTemplates", "serviceTemplates" and "partialTemplates".
{
  "generator-cg-angular": {
    "uirouter": false,
    "partialDirectory": "partial/",
    "directiveDirectory": "directive/",
    "filterDirectory": "filter/",
    "serviceDirectory": "service/",
    "directiveComplexTemplates": "mypath/complex/templates/",
    "directiveSimpleTemplates": "mypath/simple/templates/",
    "filterTemplates": "mypath/filter/",
    "serviceTemplates": "mypath/service/",
    "partialTemplates": "mypath/partial/"
  }
}