Buildsystem/Core: Adjust header locations in CMake for collisions and shared + clean up includes from re26dbe6981

This sorts out issues with non-PCH compiles on supported platforms.

--HG--
branch : trunk

src/server/shared/Database/DatabaseWorkerPool.cpp

@@ -213,4 +213,4 @@ MySQLConnection* DatabaseWorkerPool::GetConnection()
     conn = m_bundle_conn;
     ASSERT (conn);
     return conn;
-}
+}