Redefined functions to suppress redundant leading 0s and 1s

new in mixfix annotations: "' " (quote space) separates delimiters without adding extra white space for printing;

Added the exception handler handle _ => exit 1. This will catch all errors and force an exit with error code, causing Make to fail.

intro_tacsf now includes subsetI as an introduction rule. It is needed for rules like list_into_univ

Updated comment about list_subset_univ and list_into_univ.

exit: new, for use in Makefiles

Redefined arithmetic to suppress redundant leading 0s and 1s renamed the infix 2239 to the constant Bcons, as numerals eliminate the need for the infix.