Add FAST_MODE input_mode flag and --fast CLI/Tcl option that selects older
faster ISO algorithm (may be used by other symbologies in the future)
and "Fast Encoding" checkbox to Data Matrix GUI
GUI: adds Zint version numbers to DATAMATRIX sizes.
GRIDMATRIX, MAXICODE, MICROPDF417, PDF417, QRCODE, ULTRA
DOTCODE: use pre-calculated generator poly coeffs in Reed-Solomon for
performance improvement
PDF417/MICROPDF417: use common routine pdf417_initial()
GUI: code lines <= 118, shorthand widget_obj(),
shorten calling upcean_addon_gap(), upcean_guard_descent()
various backend: var name debug -> debug_print