Saving and loading

What's new in version 0.2.1:

1. Added smooth camera. 
2. Fixed bug where at position -0 block was indestructible. It occurred due transformation form float to int and for example -0.5 became just 0.
3. Saving and loading world from hard disk drive.

Video:

Now what left is some menu updates to support loading and saving, different world saving and game will be ready for early alpha testing for public.