support second argument to User#respond_to?
Merge branch 'master' into maint
Do not parse channel argument if message has no parameters

Closes gh-160
Fix basic examples that depend on state

Due to gh-85, it's not possible to set instance variables in the
configure block. Replace those uses of instance variables that need
initialization with global variables.

For the autovoice plugin, simply recognize that its initial state is
"off".

Closes gh-84
Closes gh-110
Add Channel#remove, supporting the REMOVE command

Closes gh-102