feat(JQLite): ready() now supports document.readyState=='complete'

JQLite.ready() used for automatic bootstrapping (when jQuery is not present)
now checks if document already is ready when first called. This simplifies
bootstrapping when the angular script is loaded asynchronously.

However if other scripts with angular app code are being loaded as well
it is developers responsibility to ensure that these scripts are loaded
after angular-loader.js is evaluated and before angular.js script is
evaluated.