NEWS: mention recent changes.
Optimize most common path when resolving package dependencies.

Before that change the code would do the following:
	1- if dependency is installed, continue
	2- if dependency is queued, continue
	3- get dependency from repos

After that change the code does this:
	1- if dependency is queued, continue
	2- if dependency is installed, continue
	3- get dependency from repos

So the dependency is checked if it has been queued as the first phase, which
seems to be the most common path in most cases.