This is the new logging architecture, including
* support for multiuple logging targets like stderr and vty
* log levels in addition to categories/subsystems
* filtering based on imsi, i.e. only see events for one subscriber
* dynamically change log level for each category for each vty
This introduces a new LOGP() macro together with LOGL_* definition to
support multiple log levels (severities) throughout the codebase.
Please note that the actual logging system does not use them yet,
in this patch we simply introduce the new macros at the caller site.
Holger Hans Peter Freyther
Harald Welte