v1.0.0

Long awaited 1.0 release which adds the mention feature to replace the twitter option, and change the replaceFn to be passed only one argument (the Match object).

Breaking Changes from 0.x -> 1.x

1. twitter option removed, replaced with mention (which accepts 'twitter'
   and 'instagram' values)
2. Matching mentions (previously the twitter option) now defaults to
   being turned off. Previously, Twitter handle matching was on by
   default.
3. replaceFn option now called with just one argument: the Match
   object (previously was called with two arguments: autolinker and
   match)
4. (Used inside the replaceFn) TwitterMatch replaced with
   MentionMatch, and MentionMatch.getType() now returns 'mention'
   instead of 'twitter'
5. (Used inside the replaceFn) TwitterMatch.getTwitterHandle() ->
   MentionMatch.getMention()