drastically simplified logger code now supports logging to file and syslog

drastically simplified logger code now supports logging to file and syslog
logger is backward compatible, but future calls need only have the form:
$logger->error($msg);
$logger->warn($msg);
$logger->info($msg);
$logger->debug($msg);
$logger->internal($msg);
$logger->activity($msg);

log message format is not entirely complete yet (haven't added caller info)
syslog and file logging have been tested

added example config options for log file and activity syslog facility

removed convoluted log line from appsession

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@586 9efc2488-bf62-4759-914b-345cdb29e865