Swedish translation

Hi,

I translated the plugin to Swedish. It would be a good idea to add example translations to the ‘languages’-folder. That way it becomes evident that the files should be named rsvp-plugin-[locale].mo not rsvp-[locale].mo which took me a while to figure out.

Here’s the translation:
https://mortenochlinnea.se/wp-content/plugins/rsvp/languages/rsvp-plugin-sv_SE.zip

https://www.ads-software.com/plugins/rsvp/