filename may be omitted.

according to an idea by Harri Pasanen (but with different syntax).
This affects the 'break' and 'clear' commands and their help
functions.  Also added a helper method lookupmodule().

Also:

- Try to import readline (important when pdb is used from/as a script).
- Get rid of reference to ancient __privileged__ magic variable.
- Moved all import out of functions to the top.
- When used as a script, check that the script file exists.

of the variables known to hold arguments, but that's as close as I can
get, and generally it's close enough).

- move compile() inside try-except
- add code so you can do "python pdb.py <script> <arg> ..." to debug <script>

  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)

* builtin.py: b/w compat for builtin -> __builtin__ name change
* string.py: added atof() and atol() and corresponding exceptions
* test_types.py: added test for list sort with  user comparison function

* string.py: change whitespace to include \r, \v and \f.
  When importing strop succeeds, re-evaluate meaning of letters.

* Many modules: fixes for new, stricter, argument passing rules
  (most changes were automatic ones -- not all of this is tested!).
* gwin.py: now uses mainloop.py for its main loop and window admin.
* mainloop.py: always call dispatch() with event as a tuple!
* Fix bug in pdb's 'clear' command -- don't set the bpt but clear it!

* 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.

Added colorsys.py (color system conversions).
SV.py: new version for new svideo.h (Sjoerd).
DEVICE.py: added VIDEO event type.

Added runcall(func, *args) interfaces to profile.py, bdb.py, pdb.py, wdb.py
Added new module bisect.py and used it in sched.py.
Mostly cosmetic changes to profile.py (changed output format).

Added pdd (post-mortem debugging) method to class Pdb.

Moved class Cmd out to module cmd.py.
Rewrote implementation of stack trace to incorporate traceback objects.

Simple interface "pdb.run('<statement>')" added.