in case the parameters are out of bounds and fixes error handling
for .count(), .startswith() and .endswith() for the case of
mixed string/Unicode objects.
This patch adds Python style index semantics to PyUnicode_Count()
indices (including the special handling of negative indices).
The patch is an extended version of patch #103249 submitted
by Michael Hudson (mwh) on SF. It also includes new test cases.
use PyString_AS_STRING macro on local string object
when resizing string, make sure resized string will always be big enough
split string containing error message across two lines
add test to string_tests that causes resizing
Marc-André Lemburg
Jeremy Hylton