Output multiple whitelisted params using correct syntax

- Multiple whitelisted params are currently output as: `?key1=val1=key2=val2=key3=val3`
- This branch fixes this bug and outputs multiple params as: `?key1=val1&key2=val2&key3=val3`
- Added tests to ensure proper syntax is produced
- Entire test suite passes
- Apologies for all the whitespace changes, my editor is set to remove trailing whitespace