Bullets hit

Change bullet score to 1 each hit.
Merge pull request #4 from scmx/add-readme-file

Add README file
Merge pull request #2 from scmx/add-editorconfig

Add editorconfig for consistent indentation
Fix Tree contructor

Add trees-array
Loop through that array everytime when doing something for all trees
Extract tree position randomizer into Tree#randomizePosition()