Message 227236 - Python tracker

Here is preliminary patch which fixes case-insensitive regular expression matching of unicode strings. It is incomplete, it needs applying patches from issue17381, which fixes other aspects of case-insensitive matching.

One bug is left for Turkish letters. This matching is not transitive. Three pairs of letters should match: ı ~ I ~ i ~ İ. All other combinations should not match (ı !~ i, I !~ İ, ı !~ İ). This patch doesn't fixes this bug.