Fix couple of examples

- post_processing needed to set viewport correctly - #523
- real_time signals needed data of proper shape - #528
- spacy dito

closes #523
closes #528
I think this change should live in `gloo` (turning a 1D into an (N,1) 2D vector). I fixed a bug like this at one point already, it must have gotten lost in some more recent `gloo` updates. But it can wait until your big refactoring if you want, if so just add it to the to-do list in that issue.