prettify_hipchat: Also match non-breaking spaces
prettify_hipchat: Also match non-breaking spaces

Turns out the whitespace problem I was getting in
d6f76b336715ca0fc9a11b2d2bd26500918a0e9f was due to the fact that
HipChat sends non-breaking spaces in addition to regular spaces
(WTF?!!!?!!!), so those weren't getting trimmed.

Add non-breaking space characters to the regular expression so those get
whacked by our substitution matcher also.

teddywing/irssi-hipchat-stfu,teddywing/irssi-hipchat-stfu