poly-v0.7.0

• moved old options -1 and -c to -C gen-obj and -C clamp
• introduced structured and colored log output for clarity:
  • verbosity controlled by new option -v
  • log levels are: none, error, warn, info, note, debug; default: note
  • color controlled by repurposed option -c
  • solvers are more verbose in what they are doing
• support reading options from envvar SMLP_OPTS (if set); parsing the envvar
  string is done by the shell (envvar SHELL if set, 'sh' otherwise), as if
  SMLP was invoked by

    ${SHELL} -c 'exec "$0" ${SMLP_OPTS} "$@"' smlp arguments...