Postpone package configuration
build-x86-images.sh: remove intel-ucode from X_PKGS
README.md: the scripts are not in flux, remove obsolete comment.
Makefile: fix the clean target
Fix execution of post install scripts on cross builds
Prefer repositories from '-r' in mkplatformfs
Add support for Pinebook Pro (pinebookpro)
Added possibility to choose the partitioning software