Pages and more

[JoschD]

Thanks to jzemella:

• Implement ascii writer
• Implement ascii - pages

Problems and todo:

• code for reading pages quite sloppy -> cleanup and improvements
• I introduced a bug somewhere when cleaning up (see what happens when you run tests) Possibly, because I try to get the number of pages from the length of the data instead of setting it to 1 (see first commit in this branch).
• use test_pages.sdds to test the pages functionality