Fix bug in highlight feature

Because highlight matching was done with a global regular expression,
subsequent calls to `test` started searching after the end of the
previous match, meaning that highlight matches were often misses.
There is no reason for highlight matching to be done with a global
regular expression, so this commit fixes the issue by deleting
option 'g' from the regular expression.

In addition, I have renamed `lobby.regex` to `lobby.highlightRegExp`.