Prepare all entities to be browserified

* Use module.exports and require to make entites as modules
Ignore node_modules folder
Export Player. derp.
include browserified bundled javascript
Include Explosions
Add gulpfile to watch js, css and html file changes and browserify results in build folder
Optimize images as gulp build process
Merge pull request #7 from brunops/prepare-entities-to-be-browserified

Prepare entities to be browserified