future multi-threading for-loops

[castironpi at gmail.com]

Some iterables and control loops can be multithreaded.  Worries that
it takes a syntax change.

for X in A:
    def f( x ):
        normal suite( x )
    start_new_thread( target= f, args= ( X, ) )

Perhaps a control-flow wrapper, or method on iterable.

@parallel
for X in A:
    normal suite( X )

for X in parallel( A ):
    normal suite( X )

Discussion presued about multi-core systems.  Allow user certain
control over what runs on multi-core.  Clearly, not generally
applicable.  -- But, from __future__ import does change syntax.