About moving to xf.app.js. Idea is good, may be need to leave TODO. I won't do this now for several reason:
1. As branch name said this changes about refactoring of xf.core.js.
2. Lets keep source files as small as possible.
3. Most important is testing of AppStart function, if it will be encapsulated in xf.app.js, tests need to be rewritten dramatically, because tests won't have access to this this function.