Central Control of Assembly Versions

[raffaelfoidl]

Right now, the versions of the solution's, LicenseHeaderManager, LicenseHeaderManager.Core, LicenseHeaderManager.Console (and also die corresponding test projects) are not managed centrally. At the moment, they have to be kept in sync manually when creating a release.

They should be managed centrally, i.e. when changing the assembly version number, you should only have to touch it once. Depending on whether we want to switch to CPS style projects before, the implementation of this task may differ.