Update wkhtmltopdf to 0.12.1.

Change the build to use the embedded/patched QT for true headless
operation (similar to wip/phantomjs).

v0.12.1 (2014-06-26)
--------------------
* removed support for PostScript output which is not supported in QT5
* use OpenSSL 1.0.1g for the Windows builds
* #1502: fix spurious "exit with code 1 due to http error: 1xxx" errors
* #1504: [qt] fix rendering issues for JPEG with XMP metadata
* #1507: [qt] fix crash when CSS widows are specified
* #1509: fix TOC support which was broken after upgrade to latest Qt
* #1512: [qt] fix crashes when rendering JPEG images on Windows
  Server 2008 x64
* #1544: use UTF-8 encoding for the HTML generated by the TOC XSL
* #1545: PDFs rendering without embedded fonts on OS X
* #1546: fix problem with non-ASCII characters in output path on Windows
* #1585: delete existing files explicitly in windows installer
* #1586: [qt] suppress blank page generated if the first cell spans
  multiple pages
* #1631: [qt] crash when hiding header for a specific page
* #1686: [qt] --user-style-sheet does not work on Windows
* #1757: fix parsing of ColorMode and PrinterMode in the API
* #1764: include text codecs for Chinese (Simplified/Traditional),
  Japanese and Korean
* fix compilation failures when not building with patched Qt/WebKit
* support building with non-patched Qt4/Qt5 in either shared or static mode
* implement a --license command line option
* update URLs in the internal documentation
* generate API documentation for libwkhtmltox (on the website)
* display version in compiled binary properly under various scenarios
* complete revamp of the build system, which now generates native packages
  on all platforms

v0.12.0 (2014-02-06)
--------------------
* #443: add "sitepage" and "sitepages" support for headers
* #175: add ability to auto calculate header/footer heights
* #1086: don't return freed memory; instead use a string cache
* #648: delete infinite warnings into console about window status
* #550: enable tunneling to use a HTTP proxy for HTTPS
* #1277: avoid crash due to premature deletion of ResourceObject
* lots of fixes/enhancements for memory and error management
* add --quiet option to wkhtmltoimage
* add --cache-dir option for configuring web cache directory
* add --load-media-error-handling to handle errors for media files
* add --viewport-size to specify viewport size
* reserve heights when not using HTML header/footer
* lots of improvements in the build system
* lots of typos were fixed in various places
* [qt] rebase patch series on QT 4.8.5 (now hosted on github)
* [qt] fixes to get static builds working for MSVC 2010 (32/64 bit)
* [qt] prevent page breaks in table rows
* [qt] repeat THEAD/TFOOT when table contains page breaks
* [qt] improve font kerning as per Webkit bug 93263
* [qt] various table page-break improvements
* [qt] fix rendering due to incorrect page height computation
* [qt] implement "page-break-inside: avoid" for non-floating block
  elements
* [qt] enable WOFF file support
* [qt] add support for CSS widows and orphans for block elements

v0.11.0 rc2
-----------
* #354: Propper handling of directly embedded grayscale jpeg images
* #429: output filenames interperted as latin1 instead of utf8
* #441: Gif images do not work
* #463: Null byte in anchor name
* #635: Make /dests an indirect object
* #730: Do not assume that QPixmap requiers GUI
Update to 0.11.0. Still probably close to working.