Support for beamer notes about beamerpresenter

[stiglers-eponym]

BeamerPresenter supports loading notes and presentation from a single pdf. But this is not done automatically, you need to specify on the command line what should be interpreted as presentation and what are the notes, e.g.:
beamerpresenter --page-part=left presentation.pdf
This will load the presentation and interpret the left half of each page as the presentation, and the right half as the notes.
It is possible to provide a default value for page-part in the configuration (see man page man 5 beamerpresenter).

I often forget to test some options like page-part. If you find any bugs in these, please open an issue.

But I do see that finding the page part automatically by setting a threshold for the aspect ration would be useful.

[stiglers-eponym]

Implemented in commit 9d7cc63. Make sure your global configuration file defines page-part and page-part threshold and is stored in the right place. For \setbeameroption{show notes on second screen=right} you have to set page-part=left (because beamer refers to the part for the notes and BeamerPresenter wants the part for the presentation as an argument).