1.3

  squelched some more warnings
  added '-E' option requested by Bruno Woltzenlogel
  replaced 'cpp' by compiler $CC in 'states' script
  removed warnings for clang and gcc
  fixed issue with frame clearing (detected by warning)

1.2

  replacing fopen64 by fopen on Darwin (courtesy Scott Cotton)
  fixed 64 bit warnings in C files generated by configure

1.1

  tracechecker writes Allen Van Gelder's RPT and RES format
  tracechecker can extract a flat binary resolution proof
  minor fixes to work with '-W' and compressed traces

1.0
  
  first public release under BSD license

0.5
  
  traces are sorted with respect to clause indices
  'booleforce_init' necessary
  'tracecheck' allows single antecedent in chain
  fixed bogus error message when 'tracheck' does not find pivot

0.4

  aggressive clause reduction
  failed literals preprocessor