Fix some warnings.

- Use NSInteger as "pointer" value, since NSInteger is 32/64 bits depending on
  the compilation target, while int is always 32.
- Use NSValue hash implementation for TyphoonSelector. Casting SEL to
  NSUInteger seems to be deprecated.
- Chain convenience methods of TyphoonStoryboard to return the right type.
Make TyphoonFactoryProvider honor the component scope.

Instead of keeping the values inside the factory instance, just invoke the
component factory all the time. The component factory honors every scope
Typhoon has, and will honor any future scopes.

See #180
Modify tests a little bit for TyphoonPropertyInjection protocol.

Also, silence some warnings about properties not really being use
as readwrite and sources being compiled twice.