This is another approach for providing access to stdin/out/err via
libimagrt::runtime::Runtime.
The Runtime object does configure which output gets returned (stdout if
stdout is a tty, else stderr).
With this we can change libimagrt to read/write the store from/to
stdin/stdout without the user noticing that she does not write to stdout
but stderr.
Reading from stdin is not possible then, though.
This way we can control whether "out" output goes to stdout or stderr
without the user of the functionality knowing.
This is useful for later when we use libimagrt to automatically
read and write the store from and to stdout/in depending on whether we
are talking to a TTY or a pipe.
This merge solved a _LOT_ of conflicts and was a rather complicated one,
as parts of the conflict-resolution involved rewriting of half the
stuff.
This merge commit fixes all the things so a `cargo check --all`
succeeds, but I did not yet check whether tests run without failure.
This is the first part of a series of patches that reimplements the
logging backend to be more powerful and configurable.
This first patch adds types and infrastructure to be able to implement a
powerful logging abstraction.
It does not implement much functionality, except for a check whether a
module is enabled or not when logging (if configured in the config
file).
This patch removes unused crate imports reported by newer rust versions.
Some crates were only required for tests, some only for tests with
macro_import - these things were fixed with feature gates.
