Added _uncrustify.cfg and .uncrustify.cfg as additional local directory conf file names.

Added _uncrustify.cfg and .uncrustify.cfg as optional local directory config file names. Updated search order (check for .cfg files first). Updated xib file paragraph instructions for config file name and search location.

The first option (with underscore) was added for consistency with _clang-format naming scheme, and the second was added as a more intuitive/concise version than "uncrustifyconfig ". It's a matter of opinion for sure, but like .gitignore, I believe that non application build-related files should be preceded by a dot. Usually, the uncrustify configuration would be standardized for an organization and copied into each project, again, similar to a .gitignore file.