It should be possible to have plus sign in mail addresses

This improvement is related to a component/framework JIRA uses.

The plus sign '+' is commonly used to have alternate e-mail addresses, because most mail servers ignore whatever is after the +. The current parser doesn't parse such links because + isn't in the list of valid characters in the UrlUtils.java file.

I made a patch for this so such mails get parsed and linked correctly.It is for oscore 2.2.7