v0.12.0 is here!

Phooh...

Addded:

• Knockback
• Shotgun is shooting few bullets + spread
• Shotgun shooting animation and particles
• Changed shotgun damage
• Dust particles when walk
• Level transition
• Saving HP value between levels
• Saving last used weapon between levels

Also made a lot of thecnical changes, but the're not so global
Resolution for 16:9 monitors