Version 0.8.4

We are fix various issues this time:

• Fix hardware cursor dissapearing,

• Fix problem that cause no shield with skill "extra life"

• Fix achievement related issue

• Fix UI incorrect draw in some cases

• Enemy shield now work again as designed

But we also add some extra features:

• Swarmer damage increased by 20%

• Pause screen now shows experience and level

• Skills "boost" and "headstart" now grants temporary immortality

• At the start of the infinite mode game player will grant 3 seconds of immortality