Add filter API please

Hello,

this plugin works, but the whole code is hard to work with. There are close to no filters or actions so fix stuff.

We have a site with domain mapping and the non-domainmapped URL sometimes leaks to Twitter. We had to create our own version of the nxs_doFormatMsg() function to be able to filter what goes out to Twitter and fix it there.

Please simply add a filter for $message at the start of nxs_doFormatMsg().

Thanks,
Martin

https://wordpress.org/plugins/social-networks-auto-poster-facebook-twitter-g/