DO NOT MERGE - Enhanced API and added a spec for ORMultiMap

In addition the removeBindings api call has been removed in favour of using the newly introduced get, put and remove map level operations.
@patriknw - What do you think the best way of doing this is?

The merge that I have doesn't work (and fair enough!). So what I want to do is to remove the following elements and then merge:

```scala
_.value.diff(value)
```

I suppose I'm going to have to iterate through those and remove them one-by-one...