Log Message:
htmldoc: update to 1.9.14.

# Changes in HTMLDOC v1.9.14

- BMP image support is now deprecated and will be removed in a future
  release of HTMLDOC.
- Fixed a potential stack overflow bug with GIF images.
- Fixed the PDF creation date (Issue #455)
- Fixed a potential stack overflow bug with BMP images (Issue #456)
- Fixed a compile issue when libpng was not available (Issue #458)