- get rid of separate ARM and INJECT DURATION widths
 - allow for different external and internal representation of values
 - highlight invalid user entries
 - validation of settings depends on tool flow phase (e.g. setup)

LFSR button was permanently disabled until RUNTIME or STUCK_OPEN after PASS_THRU selected in model_menu
Is now also enabled for other fault models

Fixes saving of design constants again.

 - Always save it.
 - Having no FIUs in a config file is no longer an error
 -

Also,
 - no longer support FIU_CFG_BITS from .ini file,
 - rename injection to inject (about everywhere).

The 'optional' attribute of function parameters is documented but not implemented?!

 - objectify connection and configuration handling
 - work around Doxygen::Filter::Perl issue
 - add some missing documentation bits
 - make some functions private
 - always send 0 bytes to reset connection at the beginning