adjust tests

  Workarounds for the Clisp and CMUCL failures.

  Newer Clisp's no longer have the stack-overflow for the hash-table test, so
  enable it too.
untabify tests

  Yech. Phui. Tabs.
add EXTREMUM

  From http://www.cliki.net/EXTREMUM

  A simple version built on top of REDUCE for now.
tweak EXTREMUM

 Return NIL if the sequence is empty, instead of the NO-EXTREMUM nonsense.

 It was bad design, because it's not an error someone higher up the stack can
 sensibly handle, and handling it locally is too verbose and slow.

    (or (extremum ...) (error ...))

 expresses the common case succintly, and fits the pattern of existing
 sequence functions.

 If it is deemed necessary, we can also add &KEY DEFAULT, but that seems
 overkill and has little precedent in sequence functions.
update doc/alexandria.texinfo

  add IO chapter containing READ-FILE-INTO-{STRING,BYTE-VECTOR}

  change include/fun-alexandria-ensure-gethash.texinfo
  -> include/macro-alexandria-ensure-gethash.texinfo
fix starts-with-subseq :start1 and :start2
FORMAT-SYMBOL now uses WITH-STANDARD-IO-SYNTAX
document restrictions on GAUSSIAN-RANDOM
Improve spelling
fix contagion in IOTA when step is a complex integer and start is a float
fix docstring of IOTA
add existence of &KEY to return-values of PARSE-ORDINARY-LAMBDA-LIST