Psyllid log oddities

[wcpettus]

Two enhancements for the psyllid stdout/stderr logs:

• add date (in addition to time) stamp to log to make it easier to browse through old logs
• only last 16 characters of file name are kept in log, resulting in logs like:

  17:43:58 [ PROG] ol/run_server.cc(50): Creating server objects
  17:43:58 [ PROG] tterfly_house.cc(65): Prepared file <0>; default filename is <psyllid_out_0.egg>

As a further enhancement, the log files are very sparse - they only appear to have startup and crash information.

[nsoblath]

I moved this to https://github.com/project8/scarab/issues/17 since the logger is part of scarab.