Re-ordered operators
constants kpi and ke
formatting improvements
Merged hotfix 0.2.2
eliminated hack-y escape sequence handlers
more backspace fixes
documented backspace changes again
infer meaning of 'e'
added debug function (for science purposes only!)
added sequence operators, improved debug operator, handled KeyboardInterrupt
documented sequence operators and constants
improved e handling again
fixed Product
ignored todo.txt
added factorial and improved documentation a bit
improved formatting
flagged debug operator
implemented and documented mean and med
added length btn; fmt and speed improvements

- added and documented length button `#`
- sped up Clear function _significantly_
- formatting improvements in operators.py and rpn.py
bumped version to 0.3