Sets the log target for xPDO::_log() calls.
Valid target values include:
- 'ECHO': Returns output to the STDOUT.
- 'HTML': Returns output to the STDOUT with HTML formatting.
- 'FILE': Sends output to a log file.
- An array with at least one element with key 'target' matching one of the valid log targets listed above. For 'target' => 'FILE' you can specify a second element with key 'options' with another associative array with one or both of the elements 'filename' and 'filepath'.
Set the log target to format log messages in HTML and output to the browser.
Set the log target to output anything WARN or above to a new log file that is set with 'install.' plus a timestamp of current execution (useful for install procedures).