Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add xz(1) support to newsyslog.
Rewrite and simplify logfile compression code.

Approved by: gad
MFC after: 3 weeks

Add the ability to Bzip2 your logs.

PR: 27901
Submitted by: Anders Nordby <anders@fix.no> (stylistic changes by me)

$Id$ -> $FreeBSD$

A slight bit of code and doco cleanup, but mostly:

Add the much-needed and long-desired ability to force the log rotation
to take place on a specific day or time, and document same. This works
by extending the syntax of the `when' field to allow a restricted
ISO 8601 time specification, and performing the log rotation if newsyslog
is run during the same hour as is specified.