Implement route action parameter resolution

[davidbyoung]

For objects, resolve in this order:

• Check for DI container binding (only on closures)
• Request body
• Query string
• If nullable, use null
• Throw exception

For scalars, resolve in this order:

• Route var (cast to parameter type)
• Query string (cast to parameter type)
• If default value, use default value
• If nullable, use null
• Throw exception

[davidbyoung]

Implemented in develop