v0.1 demo

major updates:

- updated stand-alone wrapper to NW.js v0.30.0 (Chromium 66)
- added story (new locations, enemies, conversations, etc.)
- added new items (1 weapon, 1 armor, 2 helmets, 1 shield, 1 ring and 1 necklace)
- added armor stat
- added armor effectiveness stat for weapons
- added animated title screen
- added intro
- added conversations system
- added cinematics system
- added environments system
- added NPCs
- added chests
- added help window

bug fixes:

- fixed memory leak when SFX volume set to 0
- fixed SFX multiplication on certain circumstances

minor updates:

- added heal items compare in tooltip
- added DPS and armor values compare for weapons and armors in tooltip
- added comparison of stats which both items have, not just the origin
- pause/exit default action is now permanently bind to ESC key (option removed from settings)
- UI windows can now be closed with ESC
- other minor fixes and updates