I18n support

[ko31]

I'd like to use this plugin in Japanese, so I added support for internationalization.

Once this has been merged, we'll be able to translate it on the following WordPress page. https://translate.wordpress.org/projects/wp-plugins/star-cloudprnt-for-woocommerce/

By the way, the following is an example of Japanese translation in my development environment.

[Lozrus]

@ko31

This is great, thank you! We will 100% ensure that the 2.1.x and later releases are translatable, your results looks really good. My only concern, is that the version 2.1 branch is already very different to 2.0/master, so I think that I will not be able to merge in your pull request directly, or maybe only some parts of it (as usual, the order-handler.php file is the most heavily modified).

Anyway, I will test here to see which parts can be safely merged (I guess the settings pages at least) and which part I need to re-implement manually. Unless you are willing to submit a patch against the current 2.1 branch directly?

[ko31]

@Lozrus

Oh, I've forgotten to consider the version 2.1 branch... :sweat_smile:

I'd like to submit another new pull request for that branch later, so could you please ignore this pull request?

[Lozrus]

@ko31 If you're happy to submit a patch for the 2.1 branch then that is perfect :-) I'll hold off pushing any more code changes for a little while (it's good for me to focus on the documentation anyway) because a lot of the changes are structural and likely to break merging. Thanks for your very helpful contribution.

[ko31]

@Lozrus I submitted a patch for the 2.1 branch. https://github.com/star-micronics/star-cloudprnt-for-woocommerce/pull/9

Could you please close this pull request?