Bug 833011: moving WindowTracker to sdk/window/tracker module from sdk/deprecated/window-utils (the latter still exports it tho)
Merge branch '833011' of github.com:erikvold/addon-pathfinder into pathfinder

Conflicts:
	lib/sdk/deprecated/window-utils.js
	lib/sdk/windows/fennec.js
	test/windows/test-firefox-windows.js
Bug 862464: reverting changes made to system/observer in 8ac29ef6b14a0e8397e1a82b7d67e0e632252510