Allow choosing to default a library to manga mode

[xelivous]

Right now the sqlite database defaults all comics to non-manga mode, and it doesn't save the setting in the sqlite database upon closing yacreader. Choosing the default to be 1/0 depending on if the library is going to be used for manga or not would be preferable than opening up the sqlite database.

There isn't a simple command to change the default for just a single column in sqlite but most GUIs can do it. Updating the individual manga after importing them can be done with:

UPDATE comic_info set manga = 1