New option "--version"

At build time, we use the version number provided by configure.ac, which
is updated upstream when there is a new release.

man/backupninja.1

@@ -21,7 +21,7 @@ BACKUPNINJA \- A lightweight, extensible meta-backup system
 .I
 "a silent flower blossom death strike to lost data."
 .SH SYNOPSIS
-.B "backupninja [ \-h ] [ \-d ] [ \-n ] [ \-t ] [ \-f filename ] [ \-\-run filename ]"
+.B "backupninja [ \-h ] [ \-v ] [ \-d ] [ \-n ] [ \-t ] [ \-f filename ] [ \-\-run filename ]"
 .br
 .SH DESCRIPTION
 .B Backupninja 
@@ -71,6 +71,9 @@ burn CD/DVDs or create ISOs.
 .B \-h, \-\-help           
 Show summary of options
 .TP
+.B \-v, \-\-version           
+Show backupninja version number
+.TP
 .B \-d, \-\-debug          
 Run in debug mode, where all log messages are output to the current shell.
 .TP

src/Makefile.am

@@ -15,7 +15,8 @@ edit = sed \
     -e 's,@datadir\@,$(pkgdatadir),g' \
     -e "s,@libdir\@,$(pkglibdir),g" \
     -e 's,@localstatedir\@,$(localstatedir),g' \
-    -e 's,@prefix\@,$(prefix),g'
+    -e 's,@prefix\@,$(prefix),g' \
+    -e 's,@PACKAGE_VERSION\@,$(PACKAGE_VERSION),g'
 
 #install-exec-hook:
 

src/backupninja.in

@@ -278,6 +278,7 @@ script is run hourly from cron.
 
 The following options are available:
 -h, --help           This usage message
+-v, --version        Show backupninja version number
 -d, --debug          Run in debug mode, where all log messages are
                      output to the current shell.
 -f, --conffile FILE  Use FILE for the main configuration instead
@@ -431,12 +432,14 @@ function process_action() {
 setupcolors
 conffile="@CFGDIR@/backupninja.conf"
 loglevel=3
+version="@PACKAGE_VERSION@"
 
 ## process command line options
 
 while [ $# -ge 1 ]; do
    case $1 in
       -h|--help) usage;;
+      -v|--version) echo "backupninja $version";;
       -d|--debug) debug=1; export BACKUPNINJA_DEBUG=yes;;
       -t|--test) test=1;debug=1;;
       -n|--now) processnow=1;;