Now code model consumes a lot of memory. And even if we reduce memory consumtion
twice - or thrice - it won't help. If user creates project that is large enough,
he'll finally get OutOfMemoryError.

The problem is in the code model implementation design - it's too monolitic now;
objects hard reference other objects, so the entire model should necessarily
reside in memory.

Code model implementation should be redesign so that the entire model won't
reside necessarily in memory.