Preparing upload to CPAN

Hello,

I received the request several times, upload this module to CPAN. In these day, in Perl world, cpanm and Carton are useful tools for installing modules. And these tools use CPAN. I think it's time to upload this module to CPAN.

I filed an issue on GitHub below.
https://github.com/comewalk/google-api-perl-client/issues/8

Also, it includes important changes. My module has OAuth2::Client. But I think it's not good namespace for CPAN world. I should rename the module to Google::API::OAuth2::Client. I filed it at #9.
https://github.com/comewalk/google-api-perl-client/issues/9

Both of them will be solved soon.

I will let you know after fixing them and uploading to CPAN here and mailing list.

Thanks!