[#1] Build as non-root user
- use qemu to make non-root build
- needed host tools during build of qemu: all local wharfie tools and qemu-img
- needed host tools when building w/ qemu: tar, python
- biggest limitations:
--- The size of the possible input and output is hardly limitted.
--- The maximum output size is always fully allocated on disk
ingo 2018-03-09