This changes the logging categories to boolean flags instead of strings.
This simplifies the acceptance testing by avoiding accessing a scoped static thread local pointer to a thread local set of strings. It eliminates the only use of boost::thread_specific_ptr outside of lockorder debugging.
This change allows log entries to be directed to multiple categories and makes it easy to change the logging flags at runtime (e.g. via an RPC, though that isn’t done by this commit.)
It also eliminates the fDebug global.
Configuration of unknown logging categories now produces a warning.