v3 of testing for new tagging/dump/restore

[david@tethera.net]

Here is round 3 of the batch tagging stuff, but just the first six
patches, which are more or less useful without the remaining one
(although a bit epic if the only goal is add a single test).

Detailed list of changes follows, the first one is a change to the
encoding format.  Looking forward to maybe doing tricks with maildirs
and hardlinks, it seems like we might want to encode ':'. The fact
that it might help MacOS X users we can consider neutral ;).

- hex-escape.c: escape ':'
- hex-escape.c: simpler buffer size calculations.
- hex-xcode.c: uncrustify + delete extra blank lines
- hex-xcode.c: provide inplace mode for test coverage
- test/hex-escaping, copy tests for --in-place version of test
- test/database-test.c: only thaw if we froze
- random-corpus.c: use a table based scheme to favour shorted code points
- random-corpus.c: uncrustify
- random-corpus.c: delete blank line, reorder while loop
- update roundtrip test to avoid need for random-corpus tag.
- do not add tag "random-corpus" in random-corpus.c

Things that I (knowingly) ignored

- Jani suggested an extra talloc in random-corpus.c
- I left the argument format of hex-xcode alone