Better idle sleep time selection

Named pipe repair, minor improvements and other fixes

This bug happened sometimes when the user would go to a specific page in the document or tried to continue reading a PDF from a certain page other than the first one. This commit fixes this that.

This dialog will open if user keeps touch input active on a button from `bookBtnArray` for >= 500 ms.
'Pin' and 'More info' operations are currently not implemented.

This commit also fixes a segmentation fault that would be caused when deleting libraryWidget (Gutenberg) that first appeared in 4a104522.

TODO: Handle what happens when there are no books in the library
TODO: Re-generate database upon exiting USBMS session or books download (libraryWidget)
TODO: Adjust various icon width/height variables depending on the device

Thanks to @shermp for the help provided on QVectors, which I now use here instead of C-style arrays which could only have a fixed size.