Arbitrary patterns, type propagation, Markdown backend, size control

Patterns will now be logged without the need for alias patterns. In addition to let-bound patterns, now log match and function patterns, but only in %track_ debug scopes. We propagate type information top-down, so you don't need to repeat the types or write them in inconvenient places. We merge type information coming from multiple sources discarding type variables. PrintBox Markdown backend is now available, and backends are now fully configurable. There are now more tools to control size of log files: prune_upto, truncate_children, split_files_after.