In Aseba compiler, num and bool values anywhere in expr and conditional statements

Created by: ypiguet-epfl

The goal is to allow to store easily boolean values in variables and to use them in if/when/while without superfluous comparisons, and to give more flexibility in conditions. For example:

var a = prox.ground.reflected[0] > threshold
if a then
  ...
end

or

if (a > 5) ^ (b < 2) then
  ...
end

Both would require needlessly convoluted code with the current restrictions.