Clean up dev.dials.generate_tutorial_text
Clean up dev.dials.generate_tutorial_text

Main changes:
* fewer layers
* now requires --beta and/or --thaum to generate output
* output can be specified using --output
* default output in '.' rather than dials source tree

dials/dials,dials/dials,dials/dials,dials/dials,dials/dials