Adding the ability to abort xhr requests.
Adding a check to make sure aborted calls don't load static files.
Merge branch 'amd' of https://github.com/OpenF2/F2 into amd

Conflicts:
	F2.latest.js
	sdk/f2.debug.js
	sdk/f2.min.js
	sdk/f2.min.map
	sdk/src/F2.js
	sdk/src/helpers/loadApps.js
Fixing tests.
Adding "abort()" to return of F2.load.
Preventing aborted apps from loading.
Replacing placeholder node instead of appending to it.