Create Array Object

## Create Array Object

### Acceptance Criteria
1. "ArrayObject" class represents an array but with persistent keys.
1. The following array methods are implemented:
 - push
 - forEach
1. The following methods are also available:
 - get(index): Gets the value at the given index
 - getAsArray: gets the array object as an actual array
 - edit(index, value): Edits the element at the given index
 - remove(index): Deletes the array element
We shouldn't throw strings.