Configuration on demand - fixed the problems with the tooling api.

1. It was bothering me that the tooling api does not cope very well with the configuration on demand (building model was hanging in COD mode). It is fixed now in a basic way: when building model, all projects are always evaluated (regardless of the COD mode). When running tasks, the COD mode is respected and only relevant projects are evaluated (this was already working, I've just added basic coverage).
2. The implementation is not pretty - the BuildModelAction should not be concerned about COD mode. However, I wanted to get it fixed so that we have a starting point to conversation on the implementation and on the extent we want the tooling api to participate in COD.