Console logging

Messages written to stdout and stderr are redirected to NSLogger instances that have been configured with the option kLoggerOption_ConsoleLog. All instances with that option will receive a copy of the messages, on the "console" domain.

In addition to being convenient while debugging, I found this useful when debugging a remote device - a log-enabled build with console grabbing active will create a log file with all relevant information, including error messages from system libraries.

Known issues / to do
- Stopping all NSLogger instances does not revert the output to stdout and stderr original destinations. Messages are still being watched, and dropped.
- Strings longer than 1000 characters are split into several NSLogger messages.