Implements #2305 - add block user button

[johnnybigoode-zz]

Implements #2305 No local integration tests

filteReddit.js was changed so toggleString would accept an extra parameter 'saveOptions' If called the func it would remove all posts related to the string and also add it to the filter list This way, if you need to make some posts hide because you just blocked a new user, you can, without adding the blocked user to the filter list.

userInfo.js has a new if(userCard) section which adds blocking, it follows the patterns, I would kindly ask for someone to review the ajax call, I think it could be a little more cleaner

en.json has a new field for the text of the block button