prettify_hipchat: Trim whitespace
prettify_hipchat: Trim whitespace

Trim whitespace around the beginning and end of the text.

Based on http://perlmaven.com/trim.

There's some problem where some ending whitespace isn't getting trimmed
from some of the strings. Still not sure what's going on here.

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