* Reworded many log messages for better understanding.
 * Adjusted some version targets as we won't have a 2.4.2 release.
 * Added some FIXME comments

If there are no reistrations that are added to an event the event
doesn't need to be emited as nobody cares anyway. We will do this
simple check before we copy data into the event object to avoid
unnecessary calls to strdup() and other allocation functions.

<event> has been added and can be used within <kartoffelsalat>
both in <icecast> and <mount>.
<event> takes backend depending <option> child tags.
Currently supported backends:
 - log: send message to error log.
 - exec: executes a program or script.
 - url: delivers the event via HTTP.

within <mount> <on-connect> and <on-disconnect> has been replaced by
<event>. Config parser can on-the-fly convert old tags.
Also <authentication type="url"> within <mount> has been fixed
for those cases with <option name="mount_add" .../> and
<option name="mount_remove" .../> which are now on-the-fly converted
by the parser to corresponding <event> tags.

Please also see TAGs added as per #2098. Some include hints for
documentation updates needed after this change. Those updates
should take place before 2.4.2.

Renamed event_config_read() into config_reread_config() and moved
it into cfgfile.c. This allowed to delete event.[ch].
event.[ch] will later be used to implement <event>.

LOG_{ERROR|WARN|INFO|DEBUG}() -> ICECAST_LOG_{ERROR|WARN|INFO|DEBUG}(); this is to avoid collision with LOG_INFO that is defined as part of syslog.

svn path=/icecast/trunk/icecast/; revision=19257

svn path=/icecast/trunk/icecast/; revision=19229

svn path=/icecast/trunk/icecast/; revision=14031

svn path=/icecast/trunk/icecast/; revision=13553

an alternative filename in the xml.

svn path=/icecast/trunk/icecast/; revision=13541

need updating. Fixes a few unusual cases, if a mount was removed (with xml reload)
whilst no source was reserved then those stats were left behind.

svn path=/icecast/trunk/icecast/; revision=13538

xsl files and the icecast xml file when re-read. At icecast startup, the logs
are not open so these parsing messages still go to stderr.

svn path=/icecast/trunk/icecast/; revision=9758

svn path=/icecast/trunk/icecast/; revision=9286

svn path=/icecast/trunk/icecast/; revision=9160

svn path=/icecast/trunk/icecast/; revision=7595

svn path=/trunk/icecast/; revision=5807

svn path=/trunk/httpp/; revision=5792

svn path=/trunk/icecast/; revision=5786

for autoconf

svn path=/trunk/icecast/; revision=5156

so allows for continuing the log, or cycling just one log.   log filename
changes work as well.

svn path=/trunk/icecast/; revision=5129

Convert all tabs to 4 spaces. All code must now use 4 space indents.

svn path=/trunk/avl/; revision=4492

Lots of new locking happening so that it's safe to have the config file
disappear under the rest of the program

Does NOT affect currently-running sources at the moment

svn path=/trunk/icecast/; revision=4406