Add c-api methods to destroy global_settings and object settings

Note that one does not normally need to do this since they are consumed by the converter object,
however if you like to keep your objects in a unique_ptr until they are consumed this is for you
Apply settings also for headers and footers.
Fix typeof in mscv9
link to libgcc and libstdc++ statically when compiling under MinGW
switch to the wk_4.8 branch of patched QT
add python script for building on windows
rename common build script
add support for building Debian Wheezy and CentOS 5 binaries
implement workaround to support compilation under MSVC 2008

This fixes c5f98a70411386d03d6ba61245f2b691cf220282, which mistakenly
merged it three times. The check was also changed to apply only for
MSVC 2008 (and not for earlier versions)
update CHANGELOG
avoid unnecessary dependency on GStreamer
disable video support explicitly (otherwise gstreamer becomes a dependency)
Issue #1536 - Optional QPrinter::NativeFormat

Implemented --native-format-printer option on OS X to allow the user to select the QPrinter::NativeFormat printer (disabled by default)