Replace sprites

Also fixed gitignore (for windows?) to ignore JS files
Add left and right jumping, don't play left/right animations when in air
Add todos
Mod speed and fix flipped run animation
Merge remote-tracking branch 'origin/master' into 35-replace-assets
Merge pull request #88 from eonarheim/35-replace-assets

[#35] Replace assets
Close #78 IDrawable's can now be flipped on x and y