add some basic documentation about asterisk.conf (bug #4758, rewritten)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6211 65c4cc65-6c06-0410-ace0-fbb531ad65f3

doc/README.asterisk.conf

+Asterisk Main Configuration File
+-----------------------------------------------------
+Below is a sample of the main Asterisk configuration file,
+asterisk.conf. Note that this file is _not_ provided in
+sample form, because the Makefile creates it when needed
+and does not touch it when it already exists.
+
+---------------
+
+[directories]
+; Make sure these directoriess have the right permissions if not
+; running Asterisk as root 
+
+; Where the configuration files (except for this one) are located
+astetcdir => /etc/asterisk
+
+; Where the Asterisk loadable modules are located
+astmoddir => /usr/lib/asterisk/modules
+
+; Where additional 'library' elements (scripts, etc.) are located
+astvarlibdir => /var/lib/asterisk
+
+; Where AGI scripts/programs are located
+astagidir => /var/lib/asterisk/agi-bin
+
+; Where spool directories are located
+; Voicemail, monitor, dictation and other apps will create files here
+; and outgoing call files (used with pbx_spool) must be placed here
+astspooldir => /var/spool/asterisk
+
+; Where the Asterisk process ID (pid) file should be created
+astrundir => /var/run/asterisk
+
+; Where the Asterisk log files should be created
+astlogdir => /var/log/asterisk