remove dependency on qt-xmlpatterns
add version information for wkhtmltopdf and wkhtmltoimage
fix building DLL on windows to not include version number

This is based on the information given in this URL:
http://qt-project.org/faq/answer/how_can_i_add_version_information_to_my_application
include hash for latest commit as part of the version
fix compilation error C2864 under VS2010

This is due to the initialization of millimeterToPointMultiplier, which
is not allowed as per the C++ standard but apparently works with gcc. See

http://stackoverflow.com/questions/2454019/why-arent-static-const-floats-allowed