light observer/eventemitter with only on and trigger methods
There are a lot of cases that only is used trigger and on methods of observer. This module only supply these methods.
var a = new Observer()
var x = ''
a.on('foo', function () {
x += 'fizz'
})
a.on('foo', function () {
x += 'buzz'
})
a.trigger('foo')
console.log(x) // fizzbuzz
See tests