also firing loadend

supports frameworks/users relying on loadend progress event (e.g.,
sproutcore 1.9.2)

ref: https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest?redirectlocale=en-US&redirectslug=DOM%2FXMLHttpRequest%2FUsing_XMLHttpRequest#Monitoring_progress
resolved #1 #2 conflict, refactor
improved docs, @cairo140 improved facade events, removed ActiveeXObject patching (IE6 dies soon!) bumped to 1.0.4