MODIFIERS [no parameters]
by Matt Deatherage

Modifiers reads the "modifiers" register (KEYMODREG, $C025) and updates
several shell variables based on that register.

The affected variable values are:

{OpenApple}, {Option}, {UpdateMod}, {Keypad}, {Repeat}, {CapsLock},
{Control} and {Shift}.

Each variable is set to "0" if the corresponding bit in the modifiers
register is not set, or set to "1" if the bit is set.  Every variable is
reset every time MODIFIERS is executed.

Script example:

modifiers
if {CapsLock} == "1"
   echo "Caps Lock is down"
end
