fix OpenSSL build failure with perl 5.18 for mingw-w64 targets

Install only the software and not the docs because the man page
generation fails with "Expected text after =item, not a number"
due to a breaking change in POD::Simple present in perl 5.18,
which is the case on Ubuntu Trusty.
fix mingw-w64 build by removing the __WKHTMLTOX_UNDEF_QT_DLL__ hack

This was broken since cd6331b1aed95d3810fbb2a02517f8e2273d69ba due to
usage of QT resources. When building the library project, QT_DLL was
being defined which caused linkage issues. Earlier, this was worked
around by defining __WKHTMLTOX_UNDEF_QT_DLL__ which in turn caused
QT_DLL to be undefined in each source file, but this does not work
for the source file generated by rcc. A more sane approach is to
simply define QT_NODLL in case of static builds, which ensures that
QT_DLL is not defined at all via mkspecs/features/qt.prf
integrate standalone schroot setup/update scripts into the build script

A mini-DSL is used to specify steps for setting up of a target distribution,
which automatically sets it up for both the i386 and amd64 architectures.
This also allows support for other distributions to be added very easily.
improve the setup targets in the build script

* better detection of Debian/Ubuntu and derived distributions
* building on 32-bit distributions is supported (for i386 targets)
* introduce separate target to setup the MinGW-w64 toolchain
add support for CentOS 6 target in the build script
add support for Ubuntu Trusty/Precise targets in the build script
warn about running as root when performing the environment setup
allow the Qt configuration to be overriden in the build script
add a "posix-local" target to the build script
download OpenSSL tarball instead of using git for Windows builds
update to the latest QT which fixes #1686