Key pagination

LEFT / RIGHt
Saving png

SPACE key saves png from current page
Sorting array

Changed functions to sort array, instead of mapping a time-based
position.
Revert c40aa1f..99c1940

This rolls back to commit c40aa1f7a410e7e1949a96a4a9d5851a26489986.
Array sorting now is a different file
Test
Revert ce693ce..43e8ee9

This rolls back to commit ce693cef7f394f7f71f2957fd44be95675a5e90e.
Saving pages to pdf

- Navigating with cursor
- Each page is saved as a separate file