Fix ember-cli deprecations

Ember-cli is throwing deprecations due to the package no longer being
configured properly
Merge pull request #20 from bcardarella/bc-fix-for-ember-cli-deprecations

Fix ember-cli deprecations
Bumps version to 0.1.0
Adds main script back in for standard broccoli usage.
Updates broccoli-asset-rewrite dependency.
Updates version to 0.2.0
Adds generateAssetMap option.
Ups version number to 0.3.0
Fixes an issue with writing prepend to asset map.
Add hashFn option to specify custom hashing function