blackbox: logs python and extension hooks via ui.log()
Logs python and extension hooks to ui.log() for viewing in the blackbox.
Example log lines:
2013/02/09 08:35:19 durham> pythonhook-preupdate: hgext.eol.preupdate finished in 0.01 seconds
2013/02/09 08:35:19 durham> exthook-update: echo hooked finished in 0.02 seconds