Updated xml syntax definitions from kate repository.
Made regex matches respect 'case-insensitive'.

This should fix pandoc #1285.
Added blank itemDatas to alert_indent.xml.
Added gcc and isocpp, needed by cpp.
Bump version to 0.5.7.
Updated changelog.
Fix typo in list append operator in pcre-light-using code.
Merge pull request #41 from clinty/master

Fix typo in list append operator in pcre-light-using code.