dsynth - pty CRs, readelf, better log formatting

dsynth - pty CRs, readelf, better log formatting

* Remove CR's from build logs (set tty modes on the pty).

* Parse 'readelf -x .note.tag /bin/sh' to get the operating
  system and __DragonFly_version... basically the release name.
  Compare the operating system name against what we get back
  from the system as a validator.

* Improve the log format to make it more readable.  Certain elements such
  as statistics and times are right-justified.

* Filter certain log lines from stdout when curses mode is turned off.

* Highlight stdout lines for SUCCESS in green and FAILURE and red.