Summary:
Try and enforce the following rules:
- stderr is for updating the user about progress or errors
- Introduce Logging.progress that outputs to stderr, but honours --quiet
- Logging.stderr is as before
- Logging.out now prints to stderr (or to log files as before if set up) and
not stdout. If some information should go on stdout then the user should be
able to rely on it (ie, it's not just some progress message). For now only
the summary of the errors is printed on stdout by default.
- Logging.err* functions are gone. If the error is user-visible, it should be
Logging.stderr, or `failwith`. If not, go to the same log file as other
output, which personally I find much more convenient than having to dig through
2 log files every time I'm looking for some output.
Reviewed By: jberdine
Differential Revision: D5095720
fbshipit-source-id: 68999c9