enable do_braindead_shortcircuit_evaluation by default and deprecate * octave.cc (maximum_braindamage): Don't call Fdo_brainded_shortcircuit_evaluation. * pt-exp.h (tree_expression::mark_braindead_shortcircuit): Eliminate file name argument. * pt-binop.h, pt-binop.cc (tree_binary_expression::mark_braindead_shortcircuit): Likewise. * oct-parse.in.yy (if_cmd_list1, elseif_clause, loop_command): Eliminate argument from call to mark_braindead_shortcircuit. * pt-binop.h, pt-binop.cc (Vdo_braindead_shortcircuit_evaluation): Initialize to true. (tree_binary_expression::matlab_style_short_circuit_warning): New function. (tree_binary_expression::rvalue1): Call matlab_style_short_circuit_warning if short circuit evaluation occurs. (Fdo_braindead_shortcircuit_evaluation): Display deprecated warning. Delete tests for do_braindead_shortcircuit_evaluation. (tree_binary_expression::braindead_shortcircuit_warning_issued): New member variable. * NEWS: Mention change in default value and deprecated function.

## System-wide startup file for Octave.
##
## This file should contain any commands that should be executed each
## time Octave starts for every user at this site.