Project to translate smallfuck (with unbounded to the right tape) to xed.

The command created by sf2xed.py produces a replacement command that advances
the program execution by one step each time it is executed.

To produce a tape usable by the step command, input your tape in the form:

0 0 ^0 1 0

Which says there is a tape with 5 cells, second from right being 1 and all
others being 0, and the tape head is in the middle of this tape