Rewrite

Rewrite to simplify API and greatly improve performance

Refined API

• Replaces eco.getEntity() and eco.createEntity() with eco.entity()
• Replaces eco.createComponent() with eco.addComponent() and eco.removeComponent()
• Replaces eco.createIterator() with eco.filter()
• Refactor to reduce file size (minified 6.4KB, gzipped 1.94KB)

Feature complete

• Create entities
• Create components
• Iterate over entities that have a set of components
• Retrieve and set data for saving and loading