where appropriate

Windows failures.  Who's keeping a bz2 file open?

lining killed performance on certain Intel boxes, and the "aggressive"
macro itself gives most of the benefits on others.

 - Check the correct variable (str_obj, not str) for NULL
 - sep_len was already verified it wasn't 0

Fix compiler warning (and whitespace) on Mac OS 10.4.  (A lot of this code looked duplicated, I wonder if a utility function could help reduce the duplication here.)

set_exc_info(), reset_exc_info():  By exploiting the
likely (who knows?) invariant that when an exception's
`type` is NULL, its `value` and `traceback` are also NULL,
save some cycles in heavily-executed code.

This is a "a kronar saved is a kronar earned" patch:  the
speedup isn't reliably measurable, but it obviously does
reduce the operation count in the normal (no exception
raised) path through PyEval_EvalFrameEx().

The tim-exc_sanity branch tries to push this harder, but
is still blowing up (at least in part due to pre-existing
subtle bugs that appear to have no other visible
consequences!).

Not a bugfix candidate.

patterns in a string, only the number needed by the max limit.

find

find helpers; updated unicodeobject to use stringlib_count