Support in RLMArray for basic types (int, strings, etc)

[maxgoedjen]

It'd be awesome if RLMArray supported the types RLMObject does (or just plain NSArray/Swift Array types for basic types), for use cases like this:

{
"id": "1234",
"name": "test",
"tags": ["one", "two", "three"]
}

[segiddins]

Closing as a duplicate of #1120.