Implement solution reference parsing.
Preprare solution integrity checking.

The solution checking is now prepared to be implemented. Preparation
included generalization of the integrity check itself as well as
enriching the reference inteface.
Add exists check to solution integrity.
Replace typed referrers with ReferenceSourceType.
Update specs dll.
Read project references from projects.
Check project reference availability in solution.
Complete solution project reference integrity check.
Add solution integrity proofing to library.
Integrate solution checker in command line.

Integrated solution checking in command line and adjusted project reference checking to use ID instead of names in order to get "same" named project references.
Improve ProjectIntegrity construction.
Reorganize generic reference integrity tests.
Remove old nant task code.
Remove obsolete reference comparer.
Organize checks in own namespace.
Rename reference white list to registry.
Adjust registry tests.
Minor variable naming in global reference check.
Cleanup external libs tests and improve reference.

Binary references always are sourced frpom projects. External library check renaming.
Use typed specifications IsSatisfiedBy(IReference).