Optimize performance of new debug messages

[cronicc]

A lot of new log lines have been added with the CCTP and new logging categories were added (e.g. "sc"). We should verify that none of the new debug.log lines have too much of an impact on performance (see #192), and if they do optimize them or hide them behind extra switches. This should be done because some nodes are running with -debug=1, and although an impact on performance is expected then, zend should still be generally usable.