Small tweaks to support really complex datasets

In order to keep the code a bit more clear, I'd do something like:
```ruby
if ids.length == 1
  ids_field = {objectIds: ids.first}
else
  ids_field = {where: "OBJECTID >=#{ids.first} AND OBJECTID <=#{ids.last}"}
end
#...
params_data.merge! ids_field
```
my 2 cents