testpy.py: add tests for cclass with ignorecase
add_ctype_to_cc: change char_prop parameter to ascii_range.

Preparation for issue #4.
respect ascii flag when applying case fold to a char class

Issue #4
simplify the implementation
Merge branch 'master' into topic/cclass-with-ignorecase
Merge branch 'master' into topic/cclass-with-ignorecase

Conflicts:
	testpy.py
Merge branch 'master' into topic/cclass-with-ignorecase
Separate a case folding function
Add more tests
Fix character class with ignore case (Issue #4)

\p{ASCII}, \w, all POSIX brackets and their negated patterns inside a
character class must be handled specially. They should not match across
ASCII/non-ASCII boundary. Exclude them from ASCII/non-ASCII case folding.

* \p{ASCII} and [[:ascii:]] should not match across ASCII boundary. They
  don't depend on ASCII flag.
* \w and all POSIX brackets should not match across ASCII boundary when
  ASCII flag is on.
Remove unused code (Issue #4)
Merge branch 'topic/cclass-with-ignorecase'

Close #4.
Add tests for Issue #41
Character properties should respect ignore case flag (Issue #41)
Merge branch 'topic/charprop-with-ignorecase'