Make highlight color modifyable.

You can now change the highlight color at runtime by changing the
bot.hicolor variable to a function that takes and returns a message.
(Generally, assign functools.partial(bot.style.color, color=<color>))

 bot.py               | 1 +
 plugins/dict.py      | 2 +-
 plugins/google.py    | 2 +-
 plugins/plugins.py   | 4 ++--
 plugins/standard.py  | 4 ++--
 plugins/translate.py | 2 +-
 plugins/urban.py     | 4 ++--
 plugins/wikipedia.py | 2 +-
 8 files changed, 11 insertions(+), 10 deletions(-)