Core.csproj updated so that it does not rely on $(SolutionDir) but $(ProjectDir)

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4162
Core: preparation for type analysis.

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4165
PDO functions are not marked as final (can be overriden, Drupal)

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4168
Expression.Operation is public

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4169
Solution fix, zlib -> Zlib to support Unix source controls

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C4170