Added support for newsyslog.

Newsyslog
(http://www.freebsd.org/cgi/man.cgi?query=newsyslog&sektion=8) used on
FreeBSD and Mac OS X has the option to compress using bzip2.

It also starts it number suffix at 0 instead of at 1 like logrotate.

Added a check for the existing of a .bz2 extension in
`syslog-previous-file` and added a configurable start number for
rotation number suffix (`syslog-number-suffix-start`).
Merge pull request #2 from arnested/newsyslog

Added support for newsyslog.
Update version
Fixed "Invalid face reference: syslog-ip-face" error.
Removed defvar for syslog-ip-face which causes that error.
Multiple "Invalid face reference: t" fixed.

That message appeared in a *Messages* buffer (C-h e).

Faces are defined with `defface', not `defcustom', so they may be
customized and themed.
`syslog-font-lock-keywords' was modified appropriately.
Merge pull request #5 from alezost/master

"Invalid face reference" fixed
Update documentation
Update version