* lib/cm.h (cm_ecpp): Add a boolean parameter trust.
* lib/ecpp.c (cm_ecpp): Add parameter trust and call to primality test.
* src/params.h (evaluate_parameters_ecpp): Add parameter trust.
* src/params.c (print_t_options): New function.
  (print_help_ecpp): Call new function.
  (evaluate_parameters_ecpp): Add and handle parameter.
* src/ecpp (main), src/ecpp-mpi.c (main), tests/tecpp.c (test_ecpp):
  Adapt function calls.
* NEWS: Document the change.
* doc/cm.texi: Document the changes and drop the description of a
  parameter that has not been present for a while.