add different link types
always copy has_prefix_files
fix error level
testing soft linkage
add assertion
add pkgs_dirs and envs_dirs to config module
update dual mode work
add link()
minor simplification
allow selecting different link types
add missing '%'
remove unused code
add missing link type argument
remove empty dir ensure python binary is always copied
add information about how things are linked to output
add enumeration to output
add directory 'users' to list
add reasonable default values for pkgs_dirs
also select a better default list for envs directories
some simplifications, add cache location to output