slotworks: add a default state

to make local function-less calls possible
unwarper; add support for subexpressions-as-operands

That is for a stuff like that:

local a = (x < (y < 0 and -1 or 1)) and "test" or "fail"

If you think that's insane... well, you'are be right...
test/ifs: uncouple two testcases

So commenting the one won't suddenly make the other decompilable
test/expression: add simple cases for an expression-as-operand