Added LoggerRequestId interface

Logger should implement this interface to support RequestID handling
Implemented LoggerRequestId interface in syslog-logger
Implemented RequestID handling

When request comes to FastcgiDaemon2 it tries to read REQUEST_ID Fastcgi
parameter. If parameter preset and current logger supports
LoggerRequestId interface FastcgiDaemon2 sets value of this parameter as
a RequestID for current request.
Merge pull request #6 from karganov/master

Version up
fixed failed assertion during thread pool destruction
Merge pull request #7 from aeol/master

fixed failed assertion during thread pool destruction
Merge branch 'idents'
Version up to 2.10-24
Cleanup request_id if it was not passed with request
Added getRequestId method to the Request class
Set request_id for default logger in thread pool
Version up to 2.10-25
Fixed syslog format string usage
Version up to 2.10-26
Ubuntu Trusty compilability
Merge pull request #8 from avasiliev/master

Ubuntu Trusty compilability
Fix request filter condition check
Fix broken log entries in file logger