Various theme hook support files not included.

2 separate issues. Both played a part in this bug.

1. hook.func.inc and owner.theme.inc files weren't included in the theme registry. File inclusion came too late, before core's registry build took place so they were not seen.
2. There was also a little mistake by not replacing hyphens with underscores before checking the file name. File names for some-hook.func.inc are supposed to use hyphens like some-hook.vars.inc and some-hook.tpl.php files but it didn't translate the hyphens into the internal representations of "some_hook" from the theme registry.