Write build output by default to build dir

Created by: ePirat

Writing the build output to the source directory by default is very confusing when one has multiple build directories configured in different ways (like one with sanitizers enabled, one without) and really defeats the benefits of building outside the source directory.

Note: I've change the build.sh to retain the old build results path, so people that use the script will get the old behavior. I did not update the build.bat because this one is really complicated to understand and I am a bit clueless what there even the old behavior was, as it used the CMAKE_BUILD_TYPE but on Windows it seems one can has two build types that are only actually defined when building? But the CMAKE_ARCHIVE_OUTPUT_DIRECTORY is evaluated on initial configure as far as I can see, so I wonder what it would set there then…