VFS-1035 Allow make.py to execute arbitrary commands.
VFS-1035 Allow make.py to execute arbitrary commands.

onedata/oz-worker,onedata/oz-worker,onedata/oz-worker,onedata/op-worker,onedata/op-worker,onedata/cluster-worker,onedata/web-client,lopiola/gui,onedata/cluster-worker,onedata/op-worker,onedata/web-client