Changing underscore's isUndefined to typeof.
Changing underscore's isUndefined to typeof.

For some reasons, Underscore's isUndefined does not try...catch the
variable, causing the module to crash.

Mikuia/tmi.js,d-4-ni/tmi.js,Schmoopiie/tmi.js,Mikuia/tmi.js,tmijs/tmi.js,roberthartung/tmi.js