So, some minor at first glance, but very important changes (links as usual: stilker.sknt.ru)

1. Both client and server checks if user can build somewhere or not, its against cheats
2. UI slightly improved, so user see what can or can`t be built under cursor
3. Since this version planned restriction are works:
   * At any place user can build only “core” block
   * Any other blocks can be build “side by side” with core or already built blocks
   * You can`t build on some terrain types (currently on water, but in future it may vary for specific race)
4. TODO:
   * worm (almost like in ‘Dune’) - actually its 3 blocks, when new block appears side by side with “head”, one block disappear on the “tail”,
   so worm is moving, typically worm destroy user blocks, but can be killed by turrets
   * castle generation - eventually i make castles in random places with some expensive resources in the core