Implement -[RLMArray indexOfObjectWhere] and friends

And fix a crash when filtering a tableview which the test for this ran in to.

@alazier 
This is fine for now and it works for all  RLMArray variants. We can always add optimized implementations for each type - will create a ticket for this. 

> On Jul 30, 2014, at 11:42 AM, astigsen <notifications@github.com> wrote:
> 
> In Realm/RLMArray.mm:
> 
> >  }
> >  
> >  - (NSUInteger)indexOfObjectWithPredicate:(NSPredicate *)predicate
> >  {
> > -    @throw [NSException exceptionWithName:@"RLMNotImplementedException"
> > -                                   reason:@"Method not implemented" userInfo:nil];
> > +    RLMArray *objects = [self objectsWithPredicate:predicate];
> > +    if ([objects count] == 0) {
> > +        return NSNotFound;
> > +    }
> We are doing far too much work here. There is no need to create an RLMArray (which is a relatively expensive operation). You can use the Query::find() method to get the index directly (without creating any objects or views). It will return tightdb::not_found if there is no match.
> 
> —
> Reply to this email directly or view it on GitHub.