Encode the knowledge of how to add Venture to a VM with the
dependencies present in shell scripts.
Ignore more generated cruft.
Relocate all scripts that are intended to run inside the VM into a
duly named subdirectory.
Right.  Get implied working directory right.
Rename the VM to venture-vm-virtualbox, which makes much more sense to me.
Preserve the exit status of packer even in the face of tee.
More precise name for the script that actually calls packer.
The packer config builds a base vm only now.

Why?  Because installing the dependencies is slow but reliable,
whereas installing venture is (relatively) fast but error-prone.  I
therefore wish to separate the two steps and cache the result of the
first.
make is good at caching the outputs of some process based on the states of the inputs, so use it to cache the base-vm.
The base VM should not contain Venturecxx or VM_README.md (and adding
them is fast).
Remove dependency of the base vm on the settings file.

This necessitates not checking in complete_create that the packer
config is there, but that's ok.
On second thought, I want to check for the config file anyway.
Validate before doing work.  Also code style.
Explicit exit code.
Right.  Renamed the toplevel vm creation script.
This is how to build a working Venture VM in the new world order.
I think this is how we clean up after ourselves.  But do we need to
export the VM?
Actually, VirtualBox does not operate on VMs in place, but copies them
to its own space.  Therefore, the proper process is not copy and
modify but import modify and export.
Provisioning dependencies does not involve installing Venture.
The install venture in vm script should clean up its messes, and
should also inject the VM_README into the VM.