SW-29 Supported mapping collections of mappable objects

Related issue: #52 

AnnotationDrivenMapper can now map collections of mappable objects.

Suppose we have a class `StudentWithListOfGrades` that looks like follows:
``` java
class StudentWithListOfGrades {
   List<Grade> grades;
}
```
and a class `StudentWithListOfGradeSnapshots`:
``` java
class StudentWithListOfGradeSnapshots {
   List<GradeSnapshot> gradeSnapshots;
}
```
Assuming `Grade` is mappable to `GradeSnapshot`, properly annotated and working with AnnotationDrivenMapper you can map collection of `Grade` to collection of `GradeSnapshot` using annotations:
``` java
@MappableTo(StudentWithListOfGradeSnapshots.class)
class StudentWithListOfGrades {
   @Map(to = "gradeSnapshots", elementsAs = GradeSnapshot.class)
   List<Grade> grades;
}
```
and a class `StudentWithListOfGradeSnapshots`:
``` java
@MappableTo(StudentWithListOfGrades.class)
class StudentWithListOfGradeSnapshots {
   @Map(to = "grades", elementsAs = Grade.class)
   List<GradeSnapshot> gradeSnapshots;
}
```
This will also work when mapping array of `Grade` to collection of `GradeSnapshot` and vice versa.