Expose qtests through buildsystem

[Manuel Breugelmans]

A couple of weeks ago it was suggested to provide test executable location 
from the buildtool. While this is not doable for all builders (and surely not 
for all test frameworks) its the route to go for the qtest+cmake combination.

Unless I overlooked it's not yet implemented. Does anyone plan to? If not I 
could probably do it, with a bit of directions. Maybe subclass a 
ProjectTargetItem with a ProjectTestTargetItem?


Manuel