revision 1.27 of cmd.py

Flush stdout before reading next command.  Closes SF bug 526357.

cmd.py uses raw_input(); eats SIGCLD:

  I discovered a rather nasty side effect of the standard cmd.py
  library today. If it's sitting inside raw_input(), any SIGCLDs that
  get sent to your application get silently eaten and ignored. I'm
  assuming that this is something that readline is thoughtfully doing
  for me.

  This patch adds an instance attr that allows the user to select to
  not use raw_input(), but instead use sys.stdin.readline()

[Changed slightly to catch EOFError only for raw_input().]

added test script and expected output file as well
this closes patch 103297.
__all__ attributes will be added to other modules without first submitting
a patch, just adding the necessary line to the test script to verify
more-or-less correct implementation.

Use != instead of <> since <> is documented as "obsolescent".
Use "is" and "is not" when comparing with None or type objects.

the documentation; the cases `? foo' and `! foo' failed.

    1. Comments at the beginning of the module, before
       functions, and before classes have been turned
       into docstrings.

    2. Tabs are normalized to four spaces.

Also, removed the "remove" function from dircmp.py, which reimplements
list.remove() (it must have been very old).

    The module cmd requires for each do_xxx command a help_xxx
    function. I think this is a little old fashioned.

    Here is a patch: use the docstring as help if no help_xxx
    function can be found.

[I'm tempted to rip out all the help_* functions from pdb, but I'll
resist it.  Any takers?  --Guido]

cmd.py  has incorporated the changes we discussed a couple of weeks ago
	(a command queue, returning line from precmd, and stop from postcmd)
	and some changes to help that were occasioned because I wanted to
	inherit from pdb which inherits from cmd.py and the help routine
	didn't look for commands or the associated help deeply enough.

1) I added a command queue which is helpful to me (at least so far) and
   would also allow syntax like 's;s' (step; step) in conjunction with precmd
2) doc_leader allows the derived class to print a message before the help
   output.  Defaults to current practise of a blank line
3) nohelp allows one to override the 'No help on' message.  I need
    'Undefined command: "%s".  Try "help".'
4) Pass line to self.precmd to allow one to do some parsing: change first
   word to lower case, strip out a leading number, whatever.
5) Pass the result of onecmd and the input line to postcmd.  This allows
   one to ponder the stop result before it is effective.
6) emptyline() requires a   if self.lastcmd:  conditional because if the
   first command is null (<cr>), you get an infinite recursion with the
   code as it stands.

onecmd(line) must return the value returned by emptyline() or
default(line).

  constructors.  There is no backward compatibility.  Not everything has
  been tested.
* aiff.{py,doc}: deleted in favor of aifc.py (which contains its docs as
  comments)

* calendar.py: remove stuff now built in time; some cleanup and
  generalization in the calendar printing
* cmd.py: use __init__.
* tzparse.py: This module is no longer necessary -- use builtin time instead!

* changed eval() into getattr() in cmd.py
* added dirname(), basename() and (dummy) normath() to macpath.py
* renamed nntp.py to nntplib.py
* Made string.index() compatible with strop.index()
* Make string.atoi('') raise string.atoi_error rather than ValueError
* Added dirname() and normpath() to posixpath.