Dictionary Development, master branch (2017.04.28.)

It turns out that the previous version of the code worked just fine in a clean build. But when moving from the previous setup, in an incremental build, it produced an error. Making the RootMap file the "main" output of the Reflex dictionary generation is fixing this.

That's because I also moved the location of the generated .dsomap files. As a result, in an incremental build, since the new .dsomap file (in the new location) doesn't exist yet, the generation of the dictionary is sure to be triggered. While since the PCM file was left in the same place, so chances were that the dictionary would not be re-generated, and a build error would occur.

Also added some additional properties for the dictionary generator target. To make it show up more nicely in certain IDEs.

Currently https://gitlab.cern.ch/atlas/athena/merge_requests/1230 is waiting for this update, and https://gitlab.cern.ch/atlas/athena/merge_requests/1237 should wait for even longer, until this update is cherry-picked into the 1.0 branch. (That's less urgent anyway.)