v5.12.0

New tokens for time projections:

• %chap_time_left_eta shows the clock time you'd reach end-of-chapter at your current pace (e.g. 14:30). Closes #54.
• %book_time_left_eta does the same for end-of-book.
• %book_finish_date projects a calendar finish date based on how much you've read on this book and how often (e.g. "9 Jun"). Matches the formula KOReader's stats popup uses for "Estimated finish date".

All three accept an optional strftime brace, e.g. %chap_time_left_eta{%I:%M %p}, %book_finish_date{%a %d %b}.

%pages_per_day and %days_reading_book now divide by the number of days you've actually read this book, rather than calendar days since first opening it. For sporadically-read books these values will increase to reflect your real reading pace.