bool -- Standard Fuzion type 'bool'
We need to apologize to George Boole for crippling his name a bit,
just to safe us from typing one more letter. But at least we stop
here and do not use boo, bo or similar.
bool is a choice type that can either be TRUE of FALSE.
Note that 'TRUE' and 'FALSE' themselves are not of type 'bool'.
Routines 'true' and 'false' are the preferred way to get a constant
value of type 'bool'.
note that we do not use '==' for this to avoid confusion since
a == b == c for booleans might not behave as expected
('true <=> false <=> false' evaluates to 'true')