warn about unknown codes, use lowercase version of known unknown codes
update changes
Update Changes
critic
v0.002000

 [Dependencies::Changed / build requires]
 - Module::Build 0.4003 → 0.4004

 [Dependencies::Changed / configure requires]
 - Module::Build 0.4003 → 0.4004

 [Dependencies::Changed / develop suggests]
 - Dist::Zilla::PluginBundle::Author::KENTNL v1.7.0 → v1.7.2

 [Feature]
 - Now warns when a un-assigned section code is seen in the ansi filter.
 - If the section code is an upper case version of a lower case known one,
   lower case one is used and a warning is printed to STDERR
 - If the section code is not know, in either upper case or lower case, a
   warning is printed to STDERR and a placeholder inserted into the output
   in the form <unknow section O>

 [Packaging]
 - uses Module::Build 0.4004 test_requires