Local function CAR-SAFE is redundant/misnamed

[phoe]

See #55

serapeum/defining-types.lisp

Line 79 in 3e327de

(flet ((car-safe (x) (if (consp x) (car x) x)))

This is equivalent to ALEXANDRIA:ENSURE-CAR.

This local function's name is also a bad misnomer, since SERAPEUM:CAR-SAFE explicitly does something else than ALEXANDRIA:ENSURE-CAR in the atom case.

[phoe]

In terms of fixing #55, won't it be better in the long-term to get rid of the local functions and wrap the real SAFE-CAR in an EVAL-ALWAYS? The fewer local functions we have, the fewer places for bugs like that to hide in.