add proper option parsing to the various executables

[mhuesch]

this would allow us to add a --verbose/-v flag which could emit debug info. most of the time, we probably don't want to see that.

rle emits a potentially gigantic printout of the Sto at the end of an evaluation. we probably only want that when it's necessary.

in rli, we could support toggling verbosity (and perhaps other things) inside of the REPL, so that the whole session wouldn't have to be dumped in order to switch.