Fixed Qt configuration line to be the same in the readme and the
ext_qt CMakeLists.txt.
Added instructions for issues with missing dlls.

Added a new patch for Qt about private includes, because when using
the sources coming from the source only archive, and not the pre-built
binaries, the CMake private includes path variable is empty.

Removed fftw3 and boost special instructions, since now CMake is copying
the necessary files.