With this patch the model is:
- "print" cleans the data so that non-printable characters get
escaped. This is not necessarily reversible.
- to print in a reversible way, one can go through
escape_string(); this escapes backslashes as well to make the
decoding non-ambigious.
- Logging always escapes similar to escape_string(), making it
reversible.
Compared to master, we also change the escaping as follows:
- We now only escape with "\xXX", no more "^X" or "\0". Exception:
backslashes.
- We escape backlashes as "\\".
- There's no "alternative" output style anymore, i.e., fmt() '%A'
qualifier is gone.
Baselines in testing/btest are updated, external tests not yet.
Addresses BIT-1333.
