Two incompatible changes in system 91

[Richard M. Stallman <RMS at MIT-OZ>]

Users should note that, starting in 91.16,
 (LOGIN user host T)
means DO NOT load the init file.
 (LOGIN user host NIL)
means do load the init file.  (NIL is the default).

This is to be compatible with (LOGIN user T).

Also, the arguments to APROPOS are now keyword arguments,
except for the first one (the substring).
For example,
 (APROPOS "FOO" ':PACKAGE "ZWEI" ':PREDICATE 'FBOUNDP)