Add support for HTTP list parameters to request builder

Technically it's not a HTTP standard, but many APIs accept a 1:many relationship in HTTP parameters so long as those parameters have `[]` brackets.

Example supporting multiple user IDs:
```
api?user_ids[]=1&user_ids[]=34&user_ids[]=33
```

I'm adding support for those parameters to RequestBuilder.
Can you add descriptions to the JavaDoc on these methods that explains the format that they are putting them in so that it's clear? Explain that it's using the KEY[]=... pattern so that it's explicit and clear.