Minor changes:
- Copyright date updated to 2014;
- VersionCond class renamed to VerSubset.
New structure for package checking:
- AbstractPkgBackEnd gets methods to check requires/conflicts as well as
  for construction the designating strings for packages and relations;
- OsIntegrity class no longer performs checking by itself (see previous item);
- No longer methods for designation construction in Pkg and NamesPkgRel classes;
- PkgScopeBase no longer constructs package strings by itself.
Intermediate commit:
- VerSubset goes to Pkg.h class;
- No more Pkg.cpp file;
- The class AutoArrayAdapter<> has been removed since no longer used;
- Package lists printing in log mode is improved;
- The error strings for TaskException are improved;
- Various solver minor fixes.