Make rlwrap honour bash HISTIGNORE and HISTCONTROL options

[hanslub42]

bash users can set options HISTIGNORE and HISTCONTROL to specify when a command should not be put in the history list. rlwrap has options --forget-matching and --history-no-dupes that do the same thing, but in a slightly more complicated way.

For example, a bash user can specify HISTCONTROL=ignoredups:ignorespace, where rlwrap needs options --forget-matching='^ ' --history-no-dupes=1 to achieve the same.

As the machinery for ignoring duplicates and forgetting input is already there, it should not be too difficult to make rlwrap consult the environment (into which the bash options then have to be exported, of course) to mimic the desired bash behaviour.

zsh users (like myself) can just set the environment variables as in bash, even if zsh uses a different set of options

All this is minimally intrusive: those who don't want this can just refrain from exporting the options into the environment.