refactor(environment): rename app_path to data_path

Also, provide an additinal property called app_path that points to cwd.
Merge branch 'master' into env-hoodie-fix

Conflicts:
	lib/core/config_store.js
	lib/core/environment.js
	lib/couchdb/index.js
	lib/utils/index.js
Merge pull request #305 from hoodiehq/env-hoodie-fix

refactor(environment): rename app_path to data_path