Bug 923739 - [Messages] Words that are separated by a period are treated as Browser links regardless of content

https://bugzilla.mozilla.org/show_bug.cgi?id=923739

- Transform strings to clickable links of they match the URL expression and the matched tld portion is a valid
- Valid tlds stored in whitelist array.

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>