- started cleaning up and updating asset manager:
 * added addStore, addSerializer methods
 * split out Resource class into a seperate module
 * started cleaning up structure of load() method
 * updated specs to match api changes
-updated readme with notes about stores', parsers' and serializer's api
-updated package.json with correct dev dependencies
- updated/cleaned up all custom elements:
 * fleshed out api for asset-manager element
 * fleshed out and cleaned up all other custom elements as well