Log levels
See discussion at 4dfc89e2 (comment 6466909)
I propose
TRACE // Verbose info to follow what the program does, also in hot loops
DEBUG // Debug/Developer info about relevant events, not in hot loops
INFO // User info for regular (non-debug) events
WARNING // Something went wrong and user should be investigate
STATUS // User info for important events
ERROR // Something went wrong, needs shutdown
OFF // only for set_level()
Edited by Stephan Lachnit