All stream processors must have err outport

[emil14]

At the moment stream processors like For/Map/Filter/Reduce doesn't have err outport and there's no way to interrupt stream processing (not to be confused with #666 - that is about interruption of stream generation). Also no way to properly handle error that was thrown from stream-processor's handler.

1. Implement errors.Lift and errors.Must that can convert between nodes that have err and those that doesn't have that
2. Update stream iterators and examples/tests that depends on them

• stream-processor can't stop stream from generating, (that's exactly what 666 is about) but it can (and should) stop processing next stream items. We probably gonna need to implement state package first, so this might be a separate task. For beginning we need to simply propagate errors to parent