Previously, no splitting would occur if the paragraph count exceeded the
desired number of pages by one.

Fixes #1

Also replaces a `continue` with what was likely meant to be a `break`, which
hopefully will fix #10 and #11.

Fix translation support

See merge request !4

Bump WP compatibility

See merge request !3

Bump WP compatibility

See merge request !2

Add automated WP.org deploys

See merge request !1

Build on work by @bendoh merged in f96afe53 and implement two paging options as toggles in the UI. Also makes the approach to applying the various paging types more modular and a bit easier to follow.

Lastly, WP coding standards. There's lots to clean up, so I only dealt with those bits I actually touched in the aforementioned work.

specifying page count

Add options screen and filters for number of pages. Refactor how Quicktags are inserted to support variable number of pages. Fixes #2.