walking the zip prevents minizip from re-reading the same
data repeatedly from the actual backing filesystem.
also improves most usages of minizip to allow for >4GB,
files altho we probably don't need it
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
The pack is already has its validity checked at the beginning of the
function, so we don't need to check this again after inserting it.
Also resolves a use-after-move case.
This allows the same code to be used to read into a std::string, which
allows for eliminating the vector->string transfer when reading the
manifest file.
A ContiguousContainer is a concept that includes std::array,
std::string, and std::vector.
Makes it way harder to introduce resource leaks, and plugs the existing
resource leaks in the constructor and Install() where the file wouldn't
be closed in some error cases.
