Replace the toy arena implementation with a real one,
based on allocating 8K chunks of memory by default.

from Tools/compiler/ast.txt are not used anywhere else in asttable.txt.
So remove "\&".

 - IMPORT_NAME takes an extra argument from the stack: the relativeness of
   the import. Only passed to __import__ when it's not -1.

 - __import__() takes an optional 5th argument for the same thing; it
   __defaults to -1 (old semantics: try relative, then absolute)

 - 'from . import name' imports name (be it module or regular attribute)
   from the current module's *package*. Likewise, 'from .module import name'
   will import name from a sibling to the current module.

 - Importing from outside a package is not allowed; 'from . import sys' in a
   toplevel module will not work, nor will 'from .. import sys' in a
   (single-level) package.

 - 'from __future__ import absolute_import' will turn on the new semantics
   for import and from-import: imports will be absolute, except for
   from-import with dots.

Includes tests for regular imports and importhooks, parser changes and a
NEWS item, but no compiler-package changes or documentation changes.

Sigh -- we really should have one place for all opcode metadata.

Jeremy, please review!

exceptions.  This was triggered when 'warnings' had a filter set to "error"
that caught the string exception deprecation warning.

In a Windows debug build, trying to open a file using
an empty string as the name causes assertion death
inside MS's C runtime code.  We probably need to worm
around that in many places.  I'm worming around it here
to stop the new test_with.py from assert-dying in the
Windows debug build (it calls compile() with an empty
string for "the file name", which indirectly leads to
C-level code in Python trying to fopen("", "r")).

This was started by Mike Bland and completed by Guido
(with help from Neal).

This still needs a __future__ statement added;
Thomas is working on Michael's patch for that aspect.

There's a small amount of code cleanup and refactoring
in ast.c, compile.c and ceval.c (I fixed the lltrace
behavior when EXT_POP is used -- however I had to make
lltrace a static global).

be complete when when checking types.

Yield cannot be tested outside a function, so add a comment to that effect.

the interpreter in 2.5 .

(Armin's SF bug report).
d = {}
d[1,] = 1
Now handled correctly

PyThreadState_Delete():  if the auto-GIL-state machinery knows about
the thread state, forget it (since the thread state is being deleted,
continuing to remember it can't help, but can hurt if another thread
happens to get created with the same thread id).

I'll backport to 2.4 next.