Keep reference entries sorted

Make function $(wildcard ...) is not guaranteed to sort the results,
so explicitly sort the entries in the reference documentation file.
setup: Check for existing files after unpacking

setup: check for existing files after unpacking the tar files, not
before, otherwise we check too early and a tar file containing a
"patches" directory will not be handled properly.
setup: Try alternative patches/series names

setup: If a tar file contains a patches directory or a series file,
automatically try alternative names which are less likely to collide.
setup: Run create_db

Run create_db() as part of quilt setup, so that $QUILT_PATCHES and
$QUILT_SERIES are recorded for future quilt commands.
setup/inspect: Handle zip archives

Let quilt setup handle zip archives.
setup: Fix white space handling by check_for_existing_files

Fix handling of directory names including white spaces by
check_for_existing_files. awk can't deal with tokens which include
white spaces, so use bash's read function instead.

As a side bonus, we get rid of the undocumented dependency to "uniq".
setup: Check for existing directories before unpacking

Check for existing directories before unpacking.
inspect: Refactor code to pwd_to_dir

Move the code deriving the directory from $PWD to a separate function
to avoid code duplication.
Fix typos in the Japanese translation

Anonymous contribution from the bug tracker:
https://savannah.nongnu.org/bugs/index.php?37495
pop: Fix timestamp comparison

The timestamps recorded on file systems have a limited resolution.
For this reason, a patch or file with a timestamp exactly equal to
.timestamp should be considered as more recent than .timestamp, i.e.
potentially modified since the last push or refresh. This is
particularly important for the test suite, as we can do many actions
in the same second there.
push: Always let the user force pushing a patch

Let the user force pushing a patch even if patch returns with error
code 2. The user should know better. This happens when pushing a
patch with a header but no actual contents, for example.
Fix handling of patch files with ':' in their name

avoids errors like this:
$ quilt refresh
sed: -e expression #1, char 21: unknown option to `s'
Nothing in patch patches/strange:name

[Satoru Takeuchi: suggested first alternative implementation not
 relying on find -printf.]
[Jean Delvare: added missing quoting and a new test file for this
 case.]
push: Fix variable usage in interrupt

While bash allows poking at a function caller's variables, that's
not something we normally do in quilt.
top: Fix parameter quoting
rename: Fix parameter quoting
diff: Fix parameter quoting
refresh: Fix parameter quoting
remove: Fix parameter quoting
files: Fix parameter quoting
push: Fix parameter quoting