Extend EPUB setting ranges

[mickael-menu]

• Fix a regression of Fix turning pages with an odd count of columns #14. The pageWidth was not calculated yet when checking for the virtual column.
• Remove WebView listener on page fragment view destruction.
• Set the minimum value for all range settings to 0. It's left to the host app to choose a sane range (or not for maximum user control).
  Except for:
  • fontSize: 0 makes the text disappear and breaks the pagination.
  • lineHeight: <1 makes the lines overlap which is not readable.
  • typeScale: <1 makes the headers smaller than body, which doesn't make sense.