v2.0.0-beta.8

• fix(reducer): MERGE action added and SET action to reverted to v1 behavior - #255
• feat(populate): population of ordered data - #239
• feat(populate) populate once queries - #256
• feat(auth): emptyOnLogin config option added (defaults to true) - #254
• feat(query): emit NO_VALUE for once queries that are empty - #265
• fix(populate) Fixed populate function to return null for null paths
• app instance handling now uses firebase_ instead of extendApp (more functionality) - #250
• Removed no longer in use code from v1 (validateConfig)