Changes in version 0.27:

tarlz now prints seconds since epoch if a file date is out of range.

tarlz now uses at least 4 digits to print years.

'tarlz -tv' now prints the value of typeflag after the member name for
unknown file types.

tarlz now prints a diagnostic when it finds a corrupt tar header (or random
data where a tar header is expected).

tarlz now diagnoses CRC mismatches in extended records separately.

Multi-threaded decoding now prints diagnostics about CRC mismatches and
unknown keywords in extended records in the correct order.

Many small fixes and improvements have been made to the code and the manual.

The chapter 'Creating backups safely' has been added to the manual.
(Suggested by Aren Tyr).

Lzip is now required to run the tests because I have not found any other
portable and reliable way to tell compressed archives from non-compressed.

Where possible, .tar archives for the testsuite are now decompressed from
their .tar.lz versions instead of distributed.

'make check' no longer tests '--mtime' with extreme dates to avoid test
failures caused by differences with the system tool 'touch'.
(Reported by Aren Tyr).

5 new test files have been added to the testsuite.
