-=cut
-VERSION HISTORY
-1.01 040618 - start (curses, some basic commands)
-1.02 040620 - function keys select command/submenu from (sub)menu
- - backspace to undo last digit
-1.03 040625 - values displayable in arbitrary base
- - can enter fractions (.) and negative values (_)
-1.04 0408041445 - error dialog (don't mess up screen)
- - manual command input using capital letters
- - ^L redraws screen
- 0409092200 - overhaul in stack handling
-1.05 0409101945 - hp48-like drop (backspace but not editing value)
- - error on insufficient arguments for command
- - command backspacing
- - some unit conversion (mostly lengths) from menu
- - q for sq(rt) (formerly quit, now only ^D/quit)
-1.06 0409152310 - menu contents in module
- - new commands: a?(sin|cos|tan)h, inv, !, rand
- - x and v shortkeys
-1.07 0409242350 - numeric modifiers hardcoded instead of in action hash
- - action undo: last stack alteration can be undone
- - enter on no value repeats last val on stack
- - new commands: sr/sr, shortkeys ( )
-1.08 0409262210 - additional digits were not correctly applied to negative values
- - negative numbers displayed correctly in different bases
- - second undo redoes
- - fixed %
- - stack command (cursor up) cycles through values in stack
-1.09 0409270057 - all key aliases moved to module DCT::Bindings
- 0409291215 - number of menu items depends on screen width
- 0410112130 - hooks allowing for extra code at reload, showentry, and precmd
- 2150 - all menu related functions moved to menu.pm
- 2205 - unit conversion out of main program (entirely into unitconv.pm)
- 0410120150 - backspace becomes "back" (soft drop, like old "drop")
- - normal drop command (alt+bs) removes input/stack value at once
- 0213 - $val{frac} default undefined instead of 0
-1.10 0410120245 - fixed backspace with undef fraction
- 0410130020 - altered stack not redrawn after undo
- 0410132200 - digits added/removed to/from integer part in correct number base
- 0410142145 - allow modules to not load but without error
- - display welcome at startup, also showing version and modules
- 0410150000 - preaction hook; undo functionality moved to module
- - only first module run of multiple with the same name
- 0015 - invalid commands shown as strings instead of character codes
-=cut