Text has point_size and pos properties

And text always draws in that point size, even if inside a viewbox. There are two things to fix, see todo items:

* Is the pointsize correct like this?
* How to prevent recompilation on each draw?
Include "(20 pt)" in the text and "(15 pt)" for t2 -- at first glance one might think that being in the root scene caused t1 to be larger.