Add -r that works like python -c, for one-liners

[d33tah]

Thanks for bython, I like it! Could you add -r that reads the code from argv as opposed to the filename, so that I could use it in one-liners?

[martindorey]

I was so excited but, yeah, this was the closest I got to getting it to work - no error message, which seems surprising too:

martind@stormy:~$ echo 'for i in range(10) { print("please"); }' | ~/.local/bin/bython /dev/stdin
martind@stormy:~$