Change colorizer name again to stop confusing Perl.

Perl seems to assume that a lowercase function name that is not *known*
to be a function defined in the current package might be a filehandle or
some kind of other future reserved word.

e.g. with "print foo ($message)"

Perl thinks you're trying to send $message to the filehandle foo if foo
wasn't defined in the current package (even if it's imported from
another module).

To fix this we make the function start with a capital letter (to fix the
potential reserved word warning from the last commit changing colorizer
name), and always reference the full package when using the subroutine
from outside of ksb::Debug.